DRAFT Introduce CFFI-based Python bindings

[David Bremner]

Floris Bruynooghe <flub at devork.be> writes:

>
> Lastly there are some downsides to the choices I made:
> - I ended up going squarely for CPython 3.6+.  Choosing Python
>   3 allowed better API design, e.g. with keyword-only parameters
>   etc.  Choosing CPython 3.4+ restricts the madness that can
>   happen with __del__ and gives some newer (tho now unused)
>   features in weakref.finalizer.
> - This is no longer drop-in compatible.
> - I haven't got to a stage where my initial goal of speed has
>   been proven yet.

I guess you'll have to convince the maintainers / users of alot and afew
that this makes sense before we go much further. I'd point out that
Debian stable is only at python 3.5, so that makes me a bit wary of this
(being able to run the test suite on debian stable and similar aged
distros useful for me, and I suspect other developers).

I know there are issues with memory management in the current bindings,
so that may be a strong reason to push to python 3.6; it seems to need
more investigation at the moment.

d