Add sound effects

[xehpuk]

MineSweeper/src/mine/MineMenu.java

Line 104 in 71c523d

sound.setEnabled(false); // TODO implement sound

MineSweeper/ToDo.txt

Line 22 in 7a33ff9

Sound

Ideas when to play a sound:

• new game
• stepping on a mine
• revealing safe square
• bulk-revealing safe squares