This software is Copyright (c) 2017, 2015, 2014, 2012, 2011 by Chris Weyl.

This is free software, licensed under:

  The GNU Lesser General Public License, Version 2.1, February 1999

The GNU Lesser General Public License (LGPL)
Version 2.1, February 1999

  (The master copy of this license lives on the GNU website.)

Copyright (C) 1991, 1999 Free Software Foundation, Inc. 59
51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.

[This is the first released version of the Lesser GPL. It also
counts as the successor of the GNU Library Public License,
version 2, hence the version number 2.1.]

Preamble

The licenses for most software are designed to take away
your freedom to share and change it. By contrast, the GNU
General Public Licenses are intended to guarantee your
freedom to share and change free software--to make sure the
software is free for all its users.

This license, the Lesser General Public License, applies to
some specially designated software packages--typically
libraries--of the Free Software Foundation and other authors
who decide to use it. You can use it too, but we suggest you
first think carefully about whether this license or the ordinary
General Public License is the better strategy to use in any
particular case, based on the explanations below.

When we speak of free software, we are referring to freedom
of use, not price. Our General Public Licenses are designed
to make sure that you have the freedom to distribute copies
of free software (and charge for this service if you wish); that
you receive source code or can get it if you want it; that you
can change the software and use pieces of it in new free
programs; and that you are informed that you can do these
things.

To protect your rights, we need to make restrictions that
forbid distributors to deny you these rights or to ask you to
surrender these rights. These restrictions translate to certain
responsibilities for you if you distribute copies of the library
or if you modify it.

For example, if you distribute copies of the library, whether
gratis or for a fee, you must give the recipients all the rights
that we gave you. You must make sure that they, too,
receive or can get the source code. If you link other code
with the library, you must provide complete object files to the
recipients, so that they can relink them with the library after
making changes to the library and recompiling it. And you
must show them these terms so they know their rights.

We protect your rights with a two-step method: (1) we
copyright the library, and (2) we offer you this license, which
gives you legal permission to copy, distribute and/or modify
the library.

To protect each distributor, we want to make it very clear
that there is no warranty for the free library. Also, if the
library is modified by someone else and passed on, the
recipients should know that what they have is not the original
version, so that the original author's reputation will not be
affected by problems that might be introduced by others.

Finally, software patents pose a constant threat to the
existence of any free program. We wish to make sure that a
company cannot effectively restrict the users of a free
program by obtaining a restrictive license from a patent
holder. Therefore, we insist that any patent license obtained
for a version of the library must be consistent with the full
freedom of use specified in this license.

Most GNU software, including some libraries, is covered by
the ordinary GNU General Public License. This license, the
GNU Lesser General Public License, applies to certain
designated libraries, and is quite different from the ordinary
General Public License. We use this license for certain
libraries in order to permit linking those libraries into non-free
programs.

When a program is linked with a library, whether statically or
using a shared library, the combination of the two is legally
speaking a combined work, a derivative of the original library.
The ordinary General Public License therefore permits such
linking only if the entire combination fits its criteria of
freedom. The Lesser General Public License permits more
lax criteria for linking other code with the library.

We call this license the "Lesser" General Public License
because it does Less to protect the user's freedom than the
ordinary General Public License. It also provides other free
software developers Less of an advantage over competing
non-free programs. These disadvantages are the reason we
use the ordinary General Public License for many libraries.
However, the Lesser license provides advantages in certain
special circumstances.

For example, on rare occasions, there may be a special
need to encourage the widest possible use of a certain
library, so that it becomes a de-facto standard. To achieve
this, non-free programs must be allowed to use the library. A
more frequent case is that a free library does the same job
as widely used non-free libraries. In this case, there is little
to gain by limiting the free library to free software only, so we
use the Lesser General Public License.

In other cases, permission to use a particular library in
non-free programs enables a greater number of people to use
a large body of free software. For example, permission to
use the GNU C Library in non-free programs enables many
more people to use the whole GNU operating system, as
well as its variant, the GNU/Linux operating system.

Although the Lesser General Public License is Less
protective of the users' freedom, it does ensure that the user
of a program that is linked with the Library has the freedom
and the wherewithal to run that program using a modified
version of the Library.

The precise terms and conditions for copying, distribution
and modification follow. Pay close attention to the difference
between a "work based on the library" and a "work that uses
the library". The former contains code derived from the
library, whereas the latter must be combined with the library
in order to run.

TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION
AND MODIFICATION

0. This License Agreement applies to any software library or
other program which contains a notice placed by the
copyright holder or other authorized party saying it may be
distributed under the terms of this Lesser General Public
License (also called "this License"). Each licensee is
addressed as "you".

A "library" means a collection of software functions and/or
data prepared so as to be conveniently linked with
application programs (which use some of those functions
and data) to form executables.

The "Library", below, refers to any such software library or
work which has been distributed under these terms. A "work
based on the Library" means either the Library or any
derivative work under copyright law: that is to say, a work
containing the Library or a portion of it, either verbatim or with
modifications and/or translated straightforwardly into another
language. (Hereinafter, translation is included without
limitation in the term "modification".)

"Source code" for a work means the preferred form of the
work for making modifications to it. For a library, complete
source code means all the source code for all modules it
contains, plus any associated interface definition files, plus
the scripts used to control compilation and installation of the
library.

Activities other than copying, distribution and modification
are not covered by this License; they are outside its scope.
The act of running a program using the Library is not
restricted, and output from such a program is covered only if
its contents constitute a work based on the Library
(independent of the use of the Library in a tool for writing it).
Whether that is true depends on what the Library does and
what the program that uses the Library does.

1. You may copy and distribute verbatim copies of the
Library's complete source code as you receive it, in any
medium, provided that you conspicuously and appropriately
publish on each copy an appropriate copyright notice and
disclaimer of warranty; keep intact all the notices that refer
to this License and to the absence of any warranty; and
distribute a copy of this License along with the Library.

You may charge a fee for the physical act of transferring a
copy, and you may at your option offer warranty protection in
exchange for a fee.

2. You may modify your copy or copies of the Library or any
portion of it, thus forming a work based on the Library, and
copy and distribute such modifications or work under the
terms of Section 1 above, provided that you also meet all of
these conditions:

     a) The modified work must itself be a software
     library.
     b) You must cause the files modified to carry
     prominent notices stating that you changed the
     files and the date of any change.
     c) You must cause the whole of the work to be
     licensed at no charge to all third parties under
     the terms of this License.
     d) If a facility in the modified Library refers to a
     function or a table of data to be supplied by an
     application program that uses the facility, other
     than as an argument passed when the facility
     is invoked, then you must make a good faith
     effort to ensure that, in the event an application
     does not supply such function or table, the
     facility still operates, and performs whatever
     part of its purpose remains meaningful.

     (For example, a function in a library to
     compute square roots has a purpose that is
     entirely well-defined independent of the
     application. Therefore, Subsection 2d requires
     that any application-supplied function or table
     used by this function must be optional: if the
     application does not supply it, the square root
     function must still compute square roots.)

     These requirements apply to the modified work
     as a whole. If identifiable sections of that work
     are not derived from the Library, and can be
     reasonably considered independent and
     separate works in themselves, then this
     License, and its terms, do not apply to those
     sections when you distribute them as separate
     works. But when you distribute the same
     sections as part of a whole which is a work
     based on the Library, the distribution of the
     whole must be on the terms of this License,
     whose permissions for other licensees extend
     to the entire whole, and thus to each and every
     part regardless of who wrote it.

     Thus, it is not the intent of this section to claim
     rights or contest your rights to work written
     entirely by you; rather, the intent is to exercise
     the right to control the distribution of derivative
     or collective works based on the Library.

     In addition, mere aggregation of another work
     not based on the Library with the Library (or
     with a work based on the Library) on a volume
     of a storage or distribution medium does not
     bring the other work under the scope of this
     License.

3. You may opt to apply the terms of the ordinary GNU
General Public License instead of this License to a given
copy of the Library. To do this, you must alter all the notices
that refer to this License, so that they refer to the ordinary
GNU General Public License, version 2, instead of to this
License. (If a newer version than version 2 of the ordinary
GNU General Public License has appeared, then you can
specify that version instead if you wish.) Do not make any
other change in these notices.

Once this change is made in a given copy, it is irreversible
for that copy, so the ordinary GNU General Public License
applies to all subsequent copies and derivative works made
from that copy.

This option is useful when you wish to copy part of the code
of the Library into a program that is not a library.

4. You may copy and distribute the Library (or a portion or
derivative of it, under Section 2) in object code or executable
form under the terms of Sections 1 and 2 above provided that
you accompany it with the complete corresponding
machine-readable source code, which must be distributed
under the terms of Sections 1 and 2 above on a medium
customarily used for software interchange.

If distribution of object code is made by offering access to
copy from a designated place, then offering equivalent
access to copy the source code from the same place
satisfies the requirement to distribute the source code, even
though third parties are not compelled to copy the source
along with the object code.

5. A program that contains no derivative of any portion of the
Library, but is designed to work with the Library by being
compiled or linked with it, is called a "work that uses the
Library". Such a work, in isolation, is not a derivative work of
the Library, and therefore falls outside the scope of this
License.

However, linking a "work that uses the Library" with the
Library creates an executable that is a derivative of the
Library (because it contains portions of the Library), rather
than a "work that uses the library". The executable is
therefore covered by this License. Section 6 states terms for
distribution of such executables.

When a "work that uses the Library" uses material from a
header file that is part of the Library, the object code for the
work may be a derivative work of the Library even though the
source code is not. Whether this is true is especially
significant if the work can be linked without the Library, or if
the work is itself a library. The threshold for this to be true is
not precisely defined by law.

If such an object file uses only numerical parameters, data
structure layouts and accessors, and small macros and
small inline functions (ten lines or less in length), then the
use of the object file is unrestricted, regardless of whether it
is legally a derivative work. (Executables containing this
object code plus portions of the Library will still fall under
Section 6.)

Otherwise, if the work is a derivative of the Library, you may
distribute the object code for the work under the terms of
Section 6. Any executables containing that work also fall
under Section 6, whether or not they are linked directly with
the Library itself.

6. As an exception to the Sections above, you may also
combine or link a "work that uses the Library" with the
Library to produce a work containing portions of the Library,
and distribute that work under terms of your choice, provided
that the terms permit modification of the work for the
customer's own use and reverse engineering for debugging
such modifications.

You must give prominent notice with each copy of the work
that the Library is used in it and that the Library and its use
are covered by this License. You must supply a copy of this
License. If the work during execution displays copyright
notices, you must include the copyright notice for the Library
among them, as well as a reference directing the user to the
copy of this License. Also, you must do one of these things:

     a) Accompany the work with the complete
     corresponding machine-readable source code
     for the Library including whatever changes were
     used in the work (which must be distributed
     under Sections 1 and 2 above); and, if the work
     is an executable linked with the Library, with
     the complete machine-readable "work that
     uses the Library", as object code and/or
     source code, so that the user can modify the
     Library and then relink to produce a modified
     executable containing the modified Library. (It
     is understood that the user who changes the
     contents of definitions files in the Library will
     not necessarily be able to recompile the
     application to use the modified definitions.)

     b) Use a suitable shared library mechanism for
     linking with the Library. A suitable mechanism
     is one that (1) uses at run time a copy of the
     library already present on the user's computer
     system, rather than copying library functions
     into the executable, and (2) will operate
     properly with a modified version of the library, if
     the user installs one, as long as the modified
     version is interface-compatible with the version
     that the work was made with.

     c) Accompany the work with a written offer,
     valid for at least three years, to give the same
     user the materials specified in Subsection 6a,
     above, for a charge no more than the cost of
     performing this distribution.

     d) If distribution of the work is made by offering
     access to copy from a designated place, offer
     equivalent access to copy the above specified
     materials from the same place.

     e) Verify that the user has already received a
     copy of these materials or that you have
     already sent this user a copy.

For an executable, the required form of the "work that uses
the Library" must include any data and utility programs
needed for reproducing the executable from it. However, as a
special exception, the materials to be distributed need not
include anything that is normally distributed (in either source
or binary form) with the major components (compiler, kernel,
and so on) of the operating system on which the executable
runs, unless that component itself accompanies the
executable.

It may happen that this requirement contradicts the license
restrictions of other proprietary libraries that do not normally
accompany the operating system. Such a contradiction
means you cannot use both them and the Library together in
an executable that you distribute.

7. You may place library facilities that are a work based on
the Library side-by-side in a single library together with other
library facilities not covered by this License, and distribute
such a combined library, provided that the separate
distribution of the work based on the Library and of the other
library facilities is otherwise permitted, and provided that you
do these two things:

     a) Accompany the combined library with a
     copy of the same work based on the Library,
     uncombined with any other library facilities.
     This must be distributed under the terms of the
     Sections above.

     b) Give prominent notice with the combined
     library of the fact that part of it is a work based
     on the Library, and explaining where to find the
     accompanying uncombined form of the same
     work.

8. You may not copy, modify, sublicense, link with, or
distribute the Library except as expressly provided under this
License. Any attempt otherwise to copy, modify, sublicense,
link with, or distribute the Library is void, and will
automatically terminate your rights under this License.
However, parties who have received copies, or rights, from
you under this License will not have their licenses terminated
so long as such parties remain in full compliance.

9. You are not required to accept this License, since you
have not signed it. However, nothing else grants you
permission to modify or distribute the Library or its derivative
works. These actions are prohibited by law if you do not
accept this License. Therefore, by modifying or distributing
the Library (or any work based on the Library), you indicate
your acceptance of this License to do so, and all its terms
and conditions for copying, distributing or modifying the
Library or works based on it.

10. Each time you redistribute the Library (or any work
based on the Library), the recipient automatically receives a
license from the original licensor to copy, distribute, link with
or modify the Library subject to these terms and conditions.
You may not impose any further restrictions on the
recipients' exercise of the rights granted herein. You are not
responsible for enforcing compliance by third parties with this
License.

11. If, as a consequence of a court judgment or allegation of
patent infringement or for any other reason (not limited to
patent issues), conditions are imposed on you (whether by
court order, agreement or otherwise) that contradict the
conditions of this License, they do not excuse you from the
conditions of this License. If you cannot distribute so as to
satisfy simultaneously your obligations under this License
and any other pertinent obligations, then as a consequence
you may not distribute the Library at all. For example, if a
patent license would not permit royalty-free redistribution of
the Library by all those who receive copies directly or
indirectly through you, then the only way you could satisfy
both it and this License would be to refrain entirely from
distribution of the Library.

If any portion of this section is held invalid or unenforceable
under any particular circumstance, the balance of the
section is intended to apply, and the section as a whole is
intended to apply in other circumstances.

It is not the purpose of this section to induce you to infringe
any patents or other property right claims or to contest
validity of any such claims; this section has the sole purpose
of protecting the integrity of the free software distribution
system which is implemented by public license practices.
Many people have made generous contributions to the wide
range of software distributed through that system in reliance
on consistent application of that system; it is up to the
author/donor to decide if he or she is willing to distribute
software through any other system and a licensee cannot
impose that choice.

This section is intended to make thoroughly clear what is
believed to be a consequence of the rest of this License.

12. If the distribution and/or use of the Library is restricted in
certain countries either by patents or by copyrighted
interfaces, the original copyright holder who places the
Library under this License may add an explicit geographical
distribution limitation excluding those countries, so that
distribution is permitted only in or among countries not thus
excluded. In such case, this License incorporates the
limitation as if written in the body of this License.

13. The Free Software Foundation may publish revised
and/or new versions of the Lesser General Public License
from time to time. Such new versions will be similar in spirit
to the present version, but may differ in detail to address new
problems or concerns.

Each version is given a distinguishing version number. If the
Library specifies a version number of this License which
applies to it and "any later version", you have the option of
following the terms and conditions either of that version or of
any later version published by the Free Software Foundation.
If the Library does not specify a license version number, you
may choose any version ever published by the Free Software
Foundation.

14. If you wish to incorporate parts of the Library into other
free programs whose distribution conditions are incompatible
with these, write to the author to ask for permission. For
software which is copyrighted by the Free Software
Foundation, write to the Free Software Foundation; we
sometimes make exceptions for this. Our decision will be
guided by the two goals of preserving the free status of all
derivatives of our free software and of promoting the sharing
and reuse of software generally.

NO WARRANTY

15. BECAUSE THE LIBRARY IS LICENSED FREE OF
CHARGE, THERE IS NO WARRANTY FOR THE LIBRARY,
TO THE EXTENT PERMITTED BY APPLICABLE LAW.
EXCEPT WHEN OTHERWISE STATED IN WRITING THE
COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE LIBRARY "AS IS" WITHOUT WARRANTY
OF ANY KIND, EITHER EXPRESSED OR IMPLIED,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE
QUALITY AND PERFORMANCE OF THE LIBRARY IS WITH
YOU. SHOULD THE LIBRARY PROVE DEFECTIVE, YOU
ASSUME THE COST OF ALL NECESSARY SERVICING,
REPAIR OR CORRECTION.

16. IN NO EVENT UNLESS REQUIRED BY APPLICABLE
LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT
HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY
AND/OR REDISTRIBUTE THE LIBRARY AS PERMITTED
ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING
ANY GENERAL, SPECIAL, INCIDENTAL OR
CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE
OR INABILITY TO USE THE LIBRARY (INCLUDING BUT
NOT LIMITED TO LOSS OF DATA OR DATA BEING
RENDERED INACCURATE OR LOSSES SUSTAINED BY
YOU OR THIRD PARTIES OR A FAILURE OF THE
LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE),
EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN
ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

END OF TERMS AND CONDITIONS
