Added Python 3 compatibility.

Open username-removed-376978 requested to merge micahcochran/bdflib:py3 into master

All tests run on Python 2.7 and Python 3.4. Replaced deprecated test names self.fail... with self.assert... General updates to setup.py. ensured that pip works. bdflib.__version__ is used to specify the version number (set to '1.0.2'). Replaced tabs in code with spaces mixed-indentation for pylint. Added README.md.