AUI-1156 - AUI TreeNode does not show "Load More Results" link

Hey @ipeychev,

Attached is an update for http://issues.liferay.com/browse/AUI-1156.

I was having trouble trying to get the IO request to work so I think I have the test as far as I can go right now without some additional guidance.  The demo I added will be very similar to the test. 

Please let me know if you have any questions.  Thanks!