glChess bug extermination

["Robert Ancell" <robert ancell gmail com>]

Hi all,

I've just had a bug squashing session to try and reduce the number of
glChess bugs in 2.20.

>From the Changelog:
lib/glchess.py: Catch and ignore all exceptions writing to stdout (Bug #426461)
lib/ai.py: Catch exception killing AI (Bug #456829)
lib/gtkui/dialogs.py: Fix exception when autoloading games with
invalid AIs (Bug #486254)
lib/gtkui/gtkui.py, glchess.in: Moved pygtk.require() to glchess.in so
it is always called first (Bug #483556)
lib/chess/lan.py, pgn.py: Add better support for informal PGN files
(Bug #488244)
lib/gtkui/dialogs.py: GtkFileChooser.get_current_folder() can return
None, handle this case (Bug #488244)
lib/scene/opengl/texture.py: Catch GLU exception building mipmaps and
fallback to standard textures (Bug #442933)

Would it be possible for those compiling to build the 2.20 branch and
confirm everything is still working? If possible can we make an early
2.20 release to avoid floods of Ubuntu bugs :)

Cheers,
--Robert