Set sys.path properly for docs to build.

We used to do it this way, I'm not sure why it was changed.
Our settings files add directories to the path, so we need to
do it here so that names will be importable.
We don't need to run sphinx on our tests.
static_template_view.models is gone, remove it from docs.
Suggestions from James: mitx is old-school, as is autogeneration.
Merge pull request #363 from edx/ned/fix-noisy-docs

Ned/fix noisy docs