Decide the Python/C++ Interface Issue

[emcd]

Maintaining one interface to a C++ back-end from Python is irritating and burdensome enough. Maintaining two (like we are currently doing) is enough to make someone not ever want to change the interface. We need to ditch either our direct CPython interface or the indirect one via Cython. (Using Cython with C++ is a rather monstrous ordeal which does not really gain us much programming efficiency. Sure, it handles a little more bookkeeping, but it also has issues, such as not being able to handle C++ references in all cases.) We should also consider SWIG as an alternative.

A firm decision to be made before an official so that we do not have people trying to develop against multiple APIs to which we are then committed.

[emcd]

Removed Cython support and factored dynamically-generated portions (extra compile flags for debugging and sanity-checking) of Python setup script into a separate file.