Update release information files. * Combined AUTHORS and CONTRIBUTORS. * Added some more folks to the AUTHORS file based on commit history. * Added Makefile recipe to dynamically generate ChangeLog from last annotated tag or a specified ref. * Added ignores for tarballs and ChangeLog.

Makefile
Makefile.in
*.la
*.lo
*.o
.deps
.libs
ltmain.sh
missing
stamp-h1
ChangeLog
configure
config.h*
config.log
config.status
config.sub
depcomp
doltcompile
doltlibtool
aclocal.m4
autom4te*
config.guess
gtk-doc.make
install-sh
libtool
*.pc
*.spec
*.tar.gz
*.tar.bz2