AUI-1165 - Node Checkpoints Module

Hi Jon,

Attached is an update for https://issues.liferay.com/browse/AUI-1165.

I was able to implement most of the changes Eduardo recommended.  I switched the class structure over to Y.Base and simplified the demo greatly.

I also commented on some lines explaining/asking about some other things Eduardo mentioned.

Please let me know your thoughts.

Thanks!