added to .gitignore
related to #14 - refactor existing stdlib unittests to idiomatic pytest
fixes #18 - correctly handling unicode conversion where appropriate

- we were not really handling unicode at all, and the existing doctest was asserting the incorrect behavior
- refactored to use six.py
- refactored a doctest affected by this fix to be py.test test (essentially a 1-to-1 port)