rewrite loc_mapper to no longer handle ambiguous course keys
To divide new course_id into org and offering
and to use migration scripts.
Make module_render use the right conversions for course_id and location
Fix Location constructors
Clean up some enrollment tests.
Changed StaticContent.compute_location to take course_key
Refactor common code into own module
Draft modulestore refactoring for opaque keys
in order to get test_publish to work.
Missing unicode string typing
Move url_reverse to BlockUsageLocator
was running via inheritance before.