+ display lack of map in a nice way, don't generate bogus preview in the background * improve map selection behavior in online mode, so that players can load a missing map and have it correctly selected after pressing F5 without any rejoin, map-reselection. also doesn't cause "different maps generated" anymore if map is missing, instead the person lacking the map gets "invalid genmap" and drops out of game immediatly

LIBRARY "openalbridge"
EXPORTS
	openal_init
	openal_close
	openal_ready
	openal_loadfile
	openal_playsound	
	openal_pausesound
	openal_stopsound
	openal_playsound_loop
	openal_stopsound_free
	openal_freesound
	openal_toggleloop
	openal_setvolume
	openal_setglobalvolume
	openal_togglemute
	openal_fade
	openal_fadein
	openal_fadeout