Changes/Bugs list for match.

1.18   Fixed a bug with #() pattern.  Fixed Chez version to print match errors
       using ~s rather than ~a for cyclic data

1.17   Added = patterns for named structure field access.

1.16   Added defstruct and rewrote define-structure macros to be
       version independent.

1.15   Fixed a bug in match-letrec.

1.14   Fixed trivial bugs in the SLIB version.

1.13   Fixed trivial bugs in the Scheme 48 version.

1.12   Added (define box-1 unbox) to Chez version so that boxes may
       be matched using structure patterns.  Changed pattern '() to
       use null? rather than equal?.

1.11   Fixed bugs in define-structure for Scheme 48 version.
       Added a match-interface for Scheme 48 version.

1.10:  Added ... in vectors.

1.09:  Added (current-expand eps-expand) for Chez version 5.

1.08:  Ported to Scheme 48.
       Added ___ and __k as synonyms for ... and ..k.
       Added match:set-... functions for setting options.
       Changed Chez version to use a property to mark structure tags.
       Added more checks to Chez version at level 0.
       Fixed ... to expand using '() rather than ().

1.07:  Fixed several bugs in first case of match-let.

1.06:  Expanded match macros in defmacros of SLIB version for MITSCHEME.
       Changed call/cc to call-with-current-continuation.
       Added eval-when to chez version so compilation works.
       Renamed chez-intro.ss to mintro-chez.ss, and also slib-intro.scm.
       Renamed README to README-match, also CHANGES.

1.05:  Allow any identifier following $ in a pattern.

1.04:  Added unreachable pattern warnings.
       In emit, not (? list?) => not (? pair?).
       Fixed wrong number of parameters for getter.

1.03:  First public release.
