A Faster Scrabble Move Generation Algorithm

[Gaddag Data Structure – A Way To Quickly Find Scrabble Words NullWords Blog](http://nullwords.wordpress.com/2013/02/27/gaddag-data-structure/)
[Jacky Tian Blog](http://blog.xjtian.com/post/50516439182/a-smarter-scrabble-ai-part-1-lexical)

GADDAG.java