Reorganize, add `setup.py` so it can be packaged

I added a `setup.py` and `setup.cfg` so this project can be packaged into an sdist/egg/wheel. I also moved stuff around to make it easier to package and I converted `README.md` into a `README.rst`, because PyPI is currently much more friendly to reST than to Markdown.

With this you should be able to:

    python setup.py install

\- or -

    python setup.py develop

\- or -

    pip install -e .