Mrtyler its queen to make it funny

Kind of a dumb rabbit hole but these changes made it easier/possible to run Testify with green tests on my local machine, which has Python 2.7.5.

The warnings.warn thing should be backwards compatible to 2.6.

I tested setup.py with a pretty barren python environment and `python setup.py develop`.

$ PYTHONPATH=~/Testify ~/Testify/bin/testify -v test --summary --exclude-suite=catbox
...
PASSED.  238 tests / 100 cases: 238 passed, 0 failed.  (Total test time 12.84s)