Improve readability; fix end-state handler.

Fixed end-state handler to stop taking Ball messages when end-state
detected.  Looking at Yahoo's results board, failing at this could
result in the system looking as if I had poor win-state detection.

Fixed win-state detection to enclose the card matrix.  This makes the
coordinate tests look like it takes coordinate pairs, which is the
effect we want, improves readability, and reduces errors.