Free python modules defined within the blendfile between loading scenes since they would end up accessing old GameLogic, Rasterizer modules as well as old game engine data in the module namespace which can cause problems.
Previously this only worked with the Blender API.
- bpy_internal_import small C file that Blender scripting and the game engine use.
- Tested with blender, blenderplayer, loading files
- Needed to use a hack to override the Main struct since the game engine doesn't set G.main
- when the sandbox is set, only internal scripts can be imported.
