* Remove authentication, including SessionAuthentication, to fix CSRF exemption by dropping CSRF check of SessionAuthentication. * Several changes to make it more clear that only POST is supported and clean up GET method testing. * Removed the temporary 403 error logging that wasn't working. * Removed test_single_access_token which was written for DOP, but doesn't work with DOT. See [MA-2122](https://openedx.atlassian.net/browse/MA-2122) for a ticket about implementing this for DOT, although it doesn't seem to be a priority. NOTE: A comment was added to the ticket explaining that this test was removed. * GET now returns default error for methods not allowed. ARCHBOM-1667
common ------ This directory contains common code shared between LMS and CMS, such as Mako templates, CSS, and Coffescript.