A couple of improvements to parametrize
- When not specifying ids, let None and bools use their native string form (like str, int, float) rather than obfuscated form used for objects
- When specifying ids, explicitly raise a ValueError if a different number of ids are specified compared to the test cases
- Add tests for both these items.
add python testing training
Merged in pfctdayelise/pytest (pull request #38)

A couple of improvements to parametrize
merge better parametrize error messages, thanks Brianna Laugher
some python2.5/3.3 fixes of Brianna's parametrize improvements
paint last line red if "failures" or "errors" occured, attribute theuni
SO-17664702: call fixture finalizers even if the fixture function
partially failed (finalizers would not always be called before)