Clean up TODO; start work on two player game
Update config for player2, begin work on player2 in mamba_snake.rb
Change @snake to @p1_snake; organize constants
Update comments at top
Add Player 2 instruction text
Add p2 collide
Update Player One and Player Two display text
Change variable names to be more specific, change You Died to Player One Died
Change so snakes start in correct positions depending on whether two player