Protects the selection, editing and drag and drop contracts of tables and
outlines by verifying the events, delegate calls and data source calls that
applications depend on. A drop retargeted between the children of an item is
delivered to that item.
* CPOutlineView: Set the retargeted drop operation in
setDropItem:dropChildIndex:.
* CPTableViewInteractionTest: Verify selection by mouse and keyboard, editing,
drag initiation and drop handling, including refusal and retargeting by the
delegate and data source.
* CPOutlineViewInteractionTest: Verify dragged items, proposed parents and child
indexes, drop retargeting, and expansion and its cancellation during a hover.
