Add option to manually choose game version from list

Version control

email qwinn, thank, and suggest offering zipped pkgs & maybe direct link to latest

Ask on the forum about splitting to two cfg files, eg gemrb.cfg & bg1.cfg, listing utility & rationale (particularly gemrb install details should be separate from game install details). Offer to code it
	best would be to read system / user (/etc|.gemrb)/gemrb.cfg, plus .gemrb/gamename.cfg