Cleanup the change management code of the CoreDataManager. This should help get at least a little bit of better behavior out of it.

Signed-off-by: Blake Skinner <bskinner@mit.edu>
Unnecessary method call; undoManager is nil by default in iOS.

Signed-off-by: Blake Skinner <bskinner@mit.edu>
Fixes the issue with merge conflicts occurring intermittently in the dining module and also fixes the disappearing images bug.

Signed-off-by: Blake Skinner <bskinner@mit.edu>
Reword this

Signed-off-by: Blake Skinner <bskinner@mit.edu>
Alternate fix for the state context bug. Instead of messing around with CDM's internals, just reset the context instead.

Signed-off-by: Blake Skinner <bskinner@mit.edu>
iOS does not have an undo manager by default and we are not assigning one so this operation is a NOP.

Signed-off-by: Blake Skinner <bskinner@mit.edu>
Merge branch 'refs/heads/3.4/bugfix/cdm-band-aid' into 3.4/master