Move docs into gh-pages branch

[mottosso]

Command reference is currently generated with Sphinx locally, and pushed to the repository alongside code. This is problematic because..

1. The user need all dependencies (Maya, Sphinx, nose, plug-ins) in order to update the docs
2. Repository bloated with generated content, hard to know what to edit when making changes.

Instead, each push should trigger a re-build of the documentation and upload into the gh-pages branch of this repository.

[monkeez]

I've started looking into this one, I had one question. When would you want to trigger the docs to deploy? Pushes to master? Releases only?

[mottosso]

Oh that would be swell, thank you. Releases only, users are recommended to only use the latest release, rather than master, and that way they would stay up to date with whichever version users have.