Blender Git Loki

BGE PyAPI Bug reported by Pitel on blenderartist.
importing "pygame" failed when running the BGE for the second time.

Rather then clearing modules, backup and restore them (as its doing with sys.path)

This way the BGE will never remember any modules imported during game play (which can cause bugs/crashes), but it also wont break pythons state by possibly removing modules that are being used internally.