Shows custom array controller that implements table view data source methods to support drag and drop, including copying objects from one window to another,
drop of URLs, and re-ordering of the content array.

Originally from "Cocoa Bindings Examples and Hints", converted to PyObjC by
u.fiedler.

.. http://homepage.mac.com/mmalc/CocoaExamples/controllers.html
   (dead link)
