edx/edx-platform — pull request #3530 by dmitchell (2014-04-29 21:25:50+00:00)
Title: Make Locators comply with UsageKey accessors

LMS-2421

Added block_type to definition and usage keys.
Changed serializers/deserializers to not have any slashes.
Reenabled disabled tests.

@nasthagiri @cpennington (delegate if you can't or don't want to review)