Add authentication and model permission checking to REST API.
Deny anonymous reading.
Merge pull request #15 from edx/dcs/authentication

Add authentication and model permission checking to REST API.
Rest Framework 2.4 requires request for serializers.HyperlinkedModelSerializer
Merge pull request #17 from edx/dcs/restframework-upgrade

Rest Framework 2.4 requires request for serializers.HyperlinkedModelSerializer
Expose course_id to the API
Merge pull request #18 from edx/dcs/MA-4

Expose course_id to the API
Use the correct course_id regex.
Merge pull request #19 from edx/dcs/course_id

Use the correct course_id regex.
Version conflict with another edx-platform dependency.
Merge pull request #20 from edx/dcs/downgrade-restframework

Version conflict with another edx-platform dependency.
Support youtube encoded videos by using a different Profile.
Add fixtures for profiles
updated tests to reflect fixture