Set up Sphinx autodoc, viewcode extensions about invoke HOT 2 CLOSED

• Tried using sphinx-apidoc but the exclude feature is really wonky (need to exclude the vendor subtree) and even if that is worked around it pulls in the invoke package...twice? IDGI. Waste of two hours.
• Manually created a tree of autodoc using stubs, including slapping docstrings on some of the major components that lacked them.

To do:

• viewcode
• Clean up docstring existence / member inclusion/exclusion, I only made sure most of the obvious crap was showing up ("good enough for now")

from invoke.

Viewcode works OK, not the prettiest thing but not awful, and does what it says on the tin. Leaving on for now.

Gonna make a new ticket for the docs improvement/cleanup...meh.

from invoke.