Remove extra Karma configs
Add Karma options to Gruntfile, update package.json with new dependencies
Shuffle jstests, rework for Mocha + Should
Add gittip:start Grunt task to make sure Gittip is running when we run Karma
Read `CANONICAL_HOST` from `local.env`

I feel like reading it as an ini is slightly hacky, but I don't really
think that spawning a process to get the env var is that great of an
idea either.

Should probably default to using process.env too, provided at least one
of the keys we're looking for is there.
Merge pull request #1696 from gittip/grunt-karma

Karma + Mocha + Should