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.
This is actually a cmake package because of how cgal-bindings build works. I had  to fake  the install target, which it doesn't generate,  and  add  the  proper profile_links targets for python packages.  I don't think you can extend  from both cmake_tools and distutils_package anyway, due to the diamon-pattern inheritance limitation.