Investigate cffi for simpler Python bindings

[jbcoe]

I have no strong reason to think it will be better but cffi https://cffi.readthedocs.io/en/latest/overview.html could be used to create Python bindings.

Maybe this would be interesting as proof-of-concept.

[ajbennieston]

It may be interesting to support this as an additional way to interact with Python, especially if we also plan to support boost.python. There would then be the option to use ctypes, cffi or boost.python depending on the requirements of the project / environment for which bindings were being generated.