Most of the code comes from bpython/intern/opy_window.c, but two
new functions were added, to access the file and image selector
windows in Blender.
* Added submodules Draw (gui) and BGL (OpenGL wrapper):
The code comes from bpython/intern/opy_draw.c, with minor changes
to integrate it in the new implementation.
* Made changes to Camera, Lamp and Image submodules:
The implementation was improved. These files should be good
starting points for interested new coders to look at, now.
* Renamed interface.[ch] to EXPP_interface.[ch] to avoid conflict:
There is another interface.h file in source/blender/include.
