Use setup.cfg to use README.md for PyPI description

[dhimmel]

Currently, we have to use README.rst for the long_description in setuptools to created the description for PyPI.

Accoridng to this tutorial, we may be able to create a setup.cfg file containing:

[metadata]
description-file = README.md

That would be awesome. This rst format and duplicating the README has been a real annoyance. Will wait on the merging of #6, so this doesn't cause any conflicts.

[dhimmel]

Just tried the method from the tutorial and no long description showed up on test PyPI.

Therefore, It seems like there is no easy way to use a markdown README for PyPI. Solutions involve requiring pandoc locally, which is a heavy dependency.

I think the best thing to do is just make the rst README for both GitHub and PyPI long_description. What an annoyance!

[dhimmel]

See 8f74660. I ended up using pandoc via a subprocess call.

I think this is a decent workaround. If pandoc isn't installed, then long_description is None. This would only matter for the installation that is getting uploaded to PyPI. I added a pandoc dependency on Travis, so if we switch to Travis deployment, then we should be all good.