Add Python Documentation with Sphinx

[aicherc]

Build python documentation with 'sphinx' into the 'docs' folder.

• Install sphinx using pip
• Make sure sphinx and deep_rf are on your enivornment's python path.
• Switch to the docs/ directory and call make html
• View the generated documentation in the docs/build/html/ folder using a web browser
  View the README for more details.

This is a work in progress (checkout the branch and make suggestions).

To Do:

• Decide if this is even useful
• Agree on a sphinx template style
• Make sure the docstring formatting is all up to date
• Add a webhook or script to build and push the html docs to the github page branch