edx/edx-platform — pull request #4606 by polesye (2014-07-30 05:44:54+00:00)
Title: Add possibility to remove group configurations. 

**Ticket**: [BLD-1049](https://openedx.atlassian.net/browse/BLD-1049)

**Acceptance criteria:**

* If any content experiments are using the Group Configuration, delete should be unavailable (provide some text inline that says that groups are in use and cannot be deleted).
* If no content experiments are using the Group Configuration, a delete link should appear that deletes the context experiment. *
* This is irreversible, so throw a similar “Delete this Group Configuration?” modal message to let the user confirm the delete.

**sandbox:** http://studio.polesye.m.sandbox.edx.org/

@cahrens , @frrrances , @mhoeber, @explorerleslie please continue review in this PR.