Creative Commons Licensing for edX

This PR adds Creative Commons Licensing to the Open edX Platform.

Review tickets
T&L https://openedx.atlassian.net/browse/TNL-195
UX https://openedx.atlassian.net/browse/UX-948
Again, you should not be modifying classes and such in response to events. You should have a model behind this class that contains the properties that you care about. Then, when the user clicks a license button, you have this callback function set an attribute on the model. Setting the attribute fires a "change" event, which triggers the `render` function, which causes the HTML to update.