Tox and Travis-CI support

I'm trying to diagnose some installation issues, since I'm trying to use lupa as a dependency in other projects. In the process, I'm using tox and Travis-CI, since I've had good experiences with those technologies in other projects, and it integrates nicely with any existing testing setup.

This is a work in progress, because currently the builds are failing:

https://travis-ci.org/campadrenalin/lupa/builds/5564186

Would love any help I can get diagnosing the issues I'm seeing. My local errors mirror the ones in that build exactly. My primary priority in the short term is getting Python 2.X to work, since then we'll have proper passing tests for at least a few environments, and then we can start in on the Python 3.X issues.