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
It looks like you're trying to write a [Model.validate](http://backbonejs.org/#Model-validate) function, but you're doing several things wrong. First, you've defined it on a view instead of on a model, so it won't be called unless you call it yourself. Second, returning anything from `validate()` should indicate an error, and it looks like you're always returning a string.