if the cursor is over the mine. We now have to
not end the game until the user SELECTS the space
the mine is at. I hadn't realized that is_empty
only works if display is True? So I moved the
game.end() to the mine class.
Need to do:
-Populate 10 mines randomly
-Have the game end when a mine is selected (figure
out how to select something)
-Figure out an algorithm to reveal squares
-Figure out how to show numbers in revealed
squares
-Add flag functionality?