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
why did you add the `course_module` variable, if it is unused? that simply adds a new pep8 violation.

also since you're here, may be better to just use `modulestore().has_course(course_key)` so we can avoid loading the course unnecessarily.