Unittests

I've integrated travis-ci and tox for easier testing in the future.  

To run the tests in python 2.6 and 2.7, just go to the root directory and type `tox`.  This creates a virtualenv, installs ez_setup, and runs your ruffus/test/run_all_unit_tests.cmd script.

Once pulled into the master branch, all future commits will be tested on the travis-ci server and any pull requests will have the build status listed here (should show up on this page as well).  You can also check out the logs for the failing builds at https://travis-ci.org/jakebiesinger/ruffus.  

To get travis-ci working on the main repo, you'll need to go to travis-ci.org and link your github account, then go to your account and click the "ON" button for bunbun/ruffus.  Apparently, "collaborator" isn't enough to let me do this for you :)