Create a view that displays the sudoku board

* As of now, the grid just displays the starting board.
  Due to scoping issues, I am not sure how to make the
  board update only changed cells after each round through
  the guessing.

Next steps:
* Fix scoping issues so that I can have an array of cells whose
  values changed when going through the 81 squares once. That way,
  the view can update only those squares, which will allow for
  animations to be possible.
* May involve creating an entire GameController element that takes
  a guesser, a view, and a board.
* Will also likely involve separating out the guessOnCell logic.