Port to Coffeescript

A new part of the v7 plan is a port to Coffeescript. I'd like to jump directly to Dart, but that's a long way off. I'm also looking to write some test code using some of the JS/CS testing frameworks: http://macwright.org/2011/10/18/adventures-in-testing.html, http://docs.jquery.com/Qunit. Refactoring has become more difficult and error prone, and I can't put off best practice forever.