Major changes:

- Include files are now put into their own separate hierarchry under
  <dore>. This should not be a problem for older code - just compile
  with `-I/usr/include/dore' or whatever. It simplifies building
  tremendously.
- We no longer have the DORE_ERRDATA and DORE_FONTDATA environmental
  variables. They are now DORE_ERRMSGFILE, which specifies the full
  pathname of the Dore' error-message file, and DORE_FONTDIR, which
  specifies the full pathname to the directory containing the Dore'
  fonts.
