Bump version
Switch DeprecationWarning tests to use warnings context

I wasn't happy with `warnings.simplefilter('default')`. There were warnings being printed to stdout that wouldn't have been there if I weren't mucking about with `warnings`. The `catch_warnings()` context manager will restore the state of `warnings` when the context is exied.

By making this change, I can remove `TestBase.tearDown()` since it is no longer needed to reset `warnings`.
Remove a print from the tests

It was inadvertently committed in 88d662a (written while working on 0516f76) while I was trying to get `__str__()` to work with `ModelFactory()`.