Change Q_IsColorString to only identify real colors

Only colors 0 to 7 exist in engine, everything else just becomes those colors.
Add COM_SetExtension from Turtle Arena
Remove unused models from server_t
Merge remote-tracking branch 'ioquake3/master'

Conflicts:
	code/server/server.h
Move 3 MAX_* from q_shared.h to bg_misc.h