test - add integration tests

Integration tests using CasperJS (and PhantomJS) is now working on
Travis CI.

Also included is a regression-tested bug fix where OR'd statements never
worked.

Other handy notes:

- Screenshots from failing CasperJS tests will get uploaded to my AWS S3
  account. This was invaluable in tracking down a failure in the Grunt
  build pipeline that was upsetting Travis.
- A minified, compiled version of the library is uploaded to my AWS S3
  account if the build is successful.