[Bug-gnubg] Documentation

[Christian Anthon]

Hi all,

I've updated the included gnu backgammon manual. It now contains the
information from the dokuwiki, the texinfo manual, and I've updated it
a bit here and there as well. The documentation is written in docbook
format, but texinfo and info files are still generated.

I'm not entirely happy about the gtktexi rendering of the manual,
especially of the tables. But I think that the gtktexi interface is
bad and should be abandoned in favor of the html version, any way.

Christian.