Stanford-Online/class2go — pull request #1750 by jrbl (2013-01-09 18:08:22+00:00)
Title: Deletable more cautious about ContentGroup removal

* ContentGroup was always being referenced, even for Deletables without
any .contentgroup_set attribute. This threw an exception when you
deleted one of these objects (such as Announcements). Now we'll be more
defensive.
(fixes #1749)
* Some cleanups to comments