Support for Sphinx

[ericchansen]

Issue created to track progress on Sphinx documentation.

Please refer to the references below for more details on Sphinx.

• Sphinx home https://www.sphinx-doc.org/en/master/
• Supported docstring types https://stackoverflow.com/questions/3898572/what-is-the-standard-python-docstring-format

[ericchansen]

I previously used Google style docstrings. I think they look pretty. Numpydoc also looks good. Down for whatever.