Switch tests to mocha and chai, create gulp task to run jshint and tests

This change switches test framework from lab to mocha with chai expect. Main motivator was scant documentation for lab, couldn't find a way to mark tests as pending and it seems to be just a wrapper for those anyway. But I have no strong feeling, would happily switch this PR back to lab.

I also removed fibrous dependency on the channels test, but all tests are failing because of the test db dependency, so I marked them as pending. Added a test task to gulp that runs js-hint and mocha tests. Right now it only runs jshint on client code, server is pissing jshint too much.

I haven't added code coverage, there are so few tests that I didn't think was worth it.