Travis CI integration for unit tests

This only provides coverage for unit tests, not for integration tests. If the plan in #34 is to provide coverage for integration tests as well, this merge only covers #34 in part. (Is it even possible to run a local web server with Travis CI?)

After merging these changes, it should be enough for you to follow steps 1 and 2 from http://docs.travis-ci.com/user/getting-started/ in order to get the system up and running.