Provide live thumbs up/down icon on submit assessment button w/ tooltip.

This is intended to help resolve the problem of mentors accidentally
rejecting submissions they intend to accept and vice versa, as mentioned in

I didn't add unit tests to submission-detail.js right now since the
code is written in a way that it's ok if it throws exceptions (the
functionality isn't critical to the functioning of the site), and it's
also kind of hard to test regardless.
Merge pull request #81 from mozilla/live-submit-feedback

Provide live thumbs up/down icon on submit assessment button w/ tooltip.
Added Submission.countReviewed() and .countUnreviewed().

This will help with #79.
added Submission.getDashboardStatistics().
Added stats dashboard at top of review queue view.
Added a single cucumber+webdriver based acceptance test.

Much of the new support code is taken from:

https://github.com/toolness/csol-acceptance-tests
added another acceptance test
added fiber-mongoose.js w/ mongoose.Model.prototype.saveAndWait().