LP1913604: Alert staff when associating item with course at a different library

LP1913604: Alert staff when associating item with course at a different library

1) Create a new course at a branch that can have items (BR3, for
   example).
2) Add an item with the circ_lib of BR3. Note that the item is
   added to the grid.
3) Add an item with a different circ_lib. Note that you get an
   alert showing that the item is not at the course's owning library.
4) Push the Cancel button.  Notice that the item is not added to the
   course.
5) Repeat step 3 and push the Confirm button.  Notice that the item is
   added to the course this time.

Signed-off-by: Jane Sandberg <sandbej@linnbenton.edu>
Signed-off-by: Michele Morgan <mmorgan@noblenet.org>