Write documentation

[lgrahl]

• Build and validate docs
• Upload docs to saltyrtc.readthedocs.org (+instructions)
• Add a section for nginx configuration (mentioned in Make TLS optional #17)
• Add type annotations

[dbrgn]

Something with Sphinx on https://readthedocs.org/ would be nice. Alternatively http://www.mkdocs.org/ is really simple.

[lgrahl]

Definitely Sphinx. Best documentation tool I've ever met. :)

[lgrahl]

Add a section for nginx configuration (mentioned in #17)

[dbrgn]

This probably shouldn't have been closed.