Create two difficulty levels for game

[chriskerrc]

Easy:

• Less snakes
• More food
• More powerups
• Slower player snake and enemies

Hard:

• More walls, with gaps in them
• More snakes

[chriskerrc]

Florence will deal with the maps

[chriskerrc]

Feedback: there are more walls on the hard map, but doesn't this make it easier to avoid the enemy snakes, because there are more obstacles between you and the snake.