Packaging RequireJS Dependencies

RequireJS is used normally (dependencies loaded individually) in development.
Flipping the RJS_OPTIMIZATION_ENABLED bit and running r.js (before compress)
will result in all dependencies being bundled and downloaded together.

@rocha @dsjen @andy-armstrong
This file is necessary for pages that don't need their own `*-main.js` file (e.g. the homepage). Duplicated requirements are excluded. See `build.js`.