remove RequireJS from bower.json (manually added)
add underscore via bower
componentize custom editor
add async via bower
stricter jshint options
add qunit via bower.

An example is also added in `public/test/example.html` and
`public/test/example.js`. Qunit+RequireJS is a bit tricky,
reference:
http://www.nathandavison.com/article/17/using-qunit-and-requirejs-to-build-modular-unit-tests