cekees/add cgal python

Added  the CGAL python bindings. The cmake-based  install is a little strange, but this is  working for me. @johannesring these might be useful for fenics. I'm guessing CGAL is mainly useful from C++, but I'm exploring the python bindings.
Remove this patch, per https://github.com/hashdist/hashstack/pull/511#issuecomment-64253938.