Setup continuous integration for tests on Travis CI.
Fix for failing tests returning a successful response code.

When the rspec tests failed, the system call was still returning a
successful exit code of 0, so Travis CI still thought things were
passing, even when they weren't.
Add mongodb setup for Travis.
Merge branch 'gem' into travisci
Merge pull request #4 from GUI/travisci

Setup Travis CI for continuous integration testing