Break stats out into their own class
Hash Table - clean up globals - phase 1
Minor cleanups
Hashtable - simplify rotation handling, and move to 64 bit.

Performance improvement: ~3% faster
Remove unused print functionality from hash-table
Remove one global variable from hash-table code.
Very slow??
Better interface for looking up zobrist values
One more hash-table global gone
ApplyMove/UndoMove
Store row/col in hashtable, not whos_turn
Remove g_board_size, and modify data we store in hashtable