Displays the date, time, and username of the most recent save and publish

Conflicts:
	cms/djangoapps/contentstore/views/item.py
Merge pull request #4342 from edx/benmcmorran/display-last-edited

Displays the date, time, and username of the most recent save and publish
Removes unnecessary PUT after DELETE
Discard changes rewrite.

STUD-1860
Merge pull request #4374 from edx/christina/discard-changes-thursday

Discard changes rewrite.
Backbone version of the course outline page

STUD-1726