moved views._get_game to models.get_game
BingoField is now the primary Model for a Word in a BingoBoard

* BingoField can now have a position=None, which means its not on the
  BingoBoard, but its associated with the BingoBoard
* BingoField now has a vote field, which can be
  positive/negative/neutral not voted)
redirect from reclaim page to the current board, if there already is one.