Replace curl.js with RequireJS and require-css.

This was pretty easy, essentially the following:

- Add RequireJS and requirejs-css into bower.json.
- Replace `curl` with `requirejs` in index.html scripts.
- Replace curl's packages hashmap with an array (for RequireJS compat).
- Replace curl's legacy loader config with RequireJS's shim config.
- Add a map config to map `css` to `require-css/css` from *all modules* (seems inefficient?).

There were other little things here and there, but nothing mind bending or earth shattering.