added GAME_SSAMMO

added GAME_SSAMMO
added another column to gameinfo for the network filter name (gamename
for master server), and now replaces spaces with _ characters
automatically when using -customgamename, added
-customgamenetworkfiltername to override this if desired

this is necessary to resolve an issue where games whose names contain
spaces were not being supported by dpmaster

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@12013 d7cf8633-e32d-0410-b094-e92efae38249