code for minesweeper game

using the UI:

1. run server_2d.py (to play standard 2-D minesweeper) or server_nd.py (to play hypermines)
2. navigate to http://localhost:6101/

mid-game screenshot of 2-D minesweeper with x-ray off:

hypermines of 3-D with x-ray on (z = dimension 0):

same game as above (z = dimension 1):