add support for setuptools setup.py pybullet for 'pip install pybullet'

rewrite MacOpenGLWindow.mm into .m version, so that setup.py can handle it.
See also test at https://pypi.python.org/pypi/pybullet/0.1.0

MANIFEST.in

@@ -0,0 +1,7 @@
+include MANIFEST.in *.txt
+recursive-include examples *.h
+recursive-include examples *.hpp
+recursive-include Extras *.h
+recursive-include Extras *.hpp
+recursive-include src *.h
+recursive-include src *.hpp