- Apply one docstring lint to the global lint list (D302 - unicode docstrings should start with u""").
- Create an inclusion list with many more docstring checks (public modules need a docstring, white space and quoting issue, check imperative mood and capitializaton). Add a couple modules to this inclusion list.
- Add tox and Travis targets for this linting.

This gives a person who wants to work on improving Galaxy's in-code docstring documentation three ways to "raise the bar" for the project. One could:
- Add more modules to the inclusion list (.ci/flake8_docstrings_include_list.txt). Many more modules should contain docstrings - especially things in galaxy-lib and web controllers.
- Add more checks to the existing inclusion list checks - I'd say D101 and/or D103 first or any of the missing D2XX or D4XX options. D102 seems a bit too ambitious and I worry it'd be too much of a burden.
- Pick some DXXX check that is ignored globally and fix it for the whole project and then remove it from the exclude list in setup.cfg.