open-babel: 2.3.2 patch to fix pybel's Molecule.draw + fix for Cairo

Added a patch that fixes Molecule.draw() in pybel.py (similar to upstream commit df59c4a630cf753723d1318c40479d48b7507e1c)
Also fixed the inclusion of the Cairo library and includes. Earlier the CMake directives were poiting to locations within the
open-babel installation. There also seemed to be a confusion between strings and arguments, giving cmake problems to understand
the directive.