Python 3 support

v0.4.0

Tagging version v0.4.0 v0.4.0

Python 3 support with correct classifiers

v.0.4.1

Tagging version v.0.4.1 v.0.4.1

Small updatess before port to py3

• run tests easily
• ability to order dicts
• access to Choices attributes by key, as a dict
• some cleanup and doc updates