Update of PR #25, with Bower update

This updates PR #25 and resolves some merge conflicts since then.

It also adds in `intl-messageformat` as a Bower dependency, since it's already since been published to Bower.
I don't like this, too much of a loose end. That's why I have been asking to bundle up both scripts into a single file, and use it from the client side as a single script that exports a function to extend handlebars in this case. /cc @ericf