Make all code PEP-8 compliant, expand tests

* Add docstrings where comments were previously used
* De-camelfy methods
* Update a few comments
* Create all data directory parents if necessary
* Expand basic test case quite a bit (it's still basic by any measure
  of learning), and format output to fit each classification test on
  a single line in a sorted list for easy reading
* Clear test data files between runs

Closes-Bug: #1
My grammar's better than that
Update usage in README for new test content