Build updates

This should eliminate our need to do a manual patch of massrel-js every time we repackage and use the file in other projects.

There's also now an 'internal' version of massrel that omits the almond shim that we've included for full file portability. The massrel.js file still includes the shim. 

Added an r.js build config file for both the usual massrel and massrel.internal files.