configure.ac and Makefile.am rewrite

Sources used:
http://www.gnu.org/software/automake/manual/automake.html
https://www.flameeyes.eu/autotools-mythbuster/

- Remove Makefile.in which was rewritten to Makefile.am
- Add configure.ac
- subs.c includes config.h to get HAVE_PANGO
- Rename INSTALL to BUILD, the INSTALL file will be managed by autotools
- Remove all autogenerated files.
- Add a smoke test
- Rename Changes to ChangeLog per GNU standards
- Add AUTHORS and NEWS
- COPYING was not added because the original source do not include a license
- Set version to 8.2.2
- Remove custom text about building on unix
  the generic INSTALL file is sufficient

DEFAULT_FDIR is no longer necessary because --datadir can be used instead, and
.fmt files will be put in the ${pkgdatadir}/abcm2ps directory.