Update dependencies.

* `commander` to 2.5.0
* `es6-shim` to 0.20.2
* `jshint` to 2.5.0 (and jshint added to `npm test`)
* `mocha` to 2.0.1

Change-Id: Ib7012ee66c1593398e5e335c1dcaa80352f91759