Use Sphinx to build documentation

[jrenaud90]

The beginnings of this were implemented in version 0.2.1, but the sphinx documentation is sparse compared to the older markdown files.

• Rewrite old markdown files into new rst files that are used by sphinx (Documentation/source/index.rst).
• Look into how to host the html documentation files on github.

Commit Workflow

• Run sphinx-apidoc to make rst files for all TidalPy modules
• Run make html (make.bat html for windows) to build the html files (these make files should be in the Documentation directory)