Addition of a Behat test-suite covering much of the core functionality of OpenCFP

I've been sitting on this for a while trying to finish up the last few feature descriptions in the Behat suite and decided to just ship it rather than wait for everything to be perfect.  That said, I consider this foundational work for continued work and I will be contributing more here.  These Behat features are a *tad* too specific, but I left them as such because I wanted something a little brittle while doing refactors in other areas.

- Adds Behat suite covering `visitor` and `speaker` primary use-cases.
- Pretty decent integration with TravisCI that *might* need some adjusting after being incorporated into `upstream/master`.  I tested on my fork and all was well. (noted in #139).
- This PR is dependent on #151 for the PhantomJS session driver.

The next work related to this will be the addition of features for conference `admin` users interacting with the admin dashboard and sub-interfaces.

**TravisCI "Shenanigans"**

Inside of `tools/travis` are a set of scripts referenced by `before_script` & `script` in the `.travis.yml` configuration. They set up things like an `smtp-sink`, Apache, database, PhantomJS, etc.  Stuff required for the headless-browser tests to run.