Added a schema description for the "jams" collection in the music model.

Now it's a lot easier to keep track of what's going on in the documents in that collection, instead of having to piece it together from what functions can do to it.
Implemented an Angular module to allow a directive for loading indicators on AJAX requests.
Controllers are now using the loading indicator module from the previous commit to present loading indicators to the user.

This is more extensible, readable, and less "hacked in" than the previous solution which was to just use state and ng-show to show and hide the indicators.
Moved the Angular controllers to the Angular module for the site.

This is a better idea for Angular reasons even though 90% of their documentation and examples just throw controllers into the global scope, relegating this good behaviour to a small note in the developer's guide for controllers.
Adding use strict to the two non-app Angular modules.