build systems (auto, msvc, PB) do not seem to have this problem.
- Change intern/python/freeze/Makefile to freeze outside of the source/ tree
- Change source/blender/bpython/Makefile to not build the frozen stuff anymore
- Change source/blender/bpython/intern/Makefile to use CURRENT_PYTHON_API
instead of FUTURE_PYTHON_API, damage control