adding autodocumentation for python and C++

[timkpaine]

Framework for #384

Relies on doxygen to autogenerate C++ documentation, integrates it with sphinx and sphinx-apidoc python documentation using breathe. Can investigate a tool like sphinx-js for hooking in javascript as well.

Initial TODOs

• add JSDoc config w/ babel support
• fix sphinx-js bug with sphinx value iteration
• hook in sphinx-js

[timkpaine]

mozilla/sphinx-js#94

[timkpaine]

@texodus good to go, i'll flesh out the rest in a separate PR

[timkpaine]

@JHawk @sc1f take a look, and start planning on writing docstrings accordingly

[texodus]

Thanks for the PR!

There are already full JSDoc strings for all public APIs. It would be nice if we could unify the docs across packages to output something consistent - I'd like to not have half of the docs in Github and half in readthedocs if possible. In the meantime, this is a strict improvement over the 0% python docs we currently publish.