beanbag-docutils has a lot of complex code, and as we go it's getting

more difficult to make changes without risking regressions.
This change introduces the beginnings of a test suite, which runs

through all the main roles, directives, and Beanbag docstring parsing to

ensure that the output we get is correct now and in the future with new

versions of Sphinx.
Some things are not tested. For instance, the image collection and

Retina handling. These are a bit more complex, and are going to require

further work before unit tests can be added.
There are a few fixes found in the unit test runs, as well as a few

small fixes to typos in docstrings and a URL tweak for Wikipedia.

Unit tests passed with Sphinx 1.8.5 (last version to support Python 2.7)

and 3.2.1 (latest public version).