Add Unit Tests

This is a rebase and continuation of #3.  Not sure how to do cross-account, cross-branch collaboration, unless you push to a branch on the main repo...

**Completed**

- Checked out `seiffert/testing`
- Rebased against `ericclemmons/master`
- Simplified `bootstrap.php.dist`
- Updated `composer.json` with dependencies needed for tests

**TODO**

- *Optional* Fix [vagrant: not found][1] error on Travis

[1]: https://travis-ci.org/ericclemmons/ECVagrantBundle/jobs/3733036