Consider generating both a setup.cfg and a setup.py

[pganssle]

Not everything you can do in setup.py is possible in setup.cfg, but it would still be good to be able to do a partial conversion - move over everything that can be moved over and leave everything else alone, generating both a setup.py and a setup.cfg.

(As an aside, sorry to bombard you with issues all at once, at the PyCon CA sprints we're working on creating a bot that does this and were thinking of using this script or some version of it as the basis for that bot)