[Loader]: Several bug fixes.

1. A module's `lang` packs were not being included *before* the module itself.

2. `before` was not working (see: #1661).

3. A `CSS` module could not require a `js` module.  (see: http://jsbin.com/hafibawa/13/edit and #1680).

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Updated five tests related to `lang` packs that I erroneously changed in #1606.