Added main game loop
Added displayling current level
Added increasing the speed of game when leveling up
Fixed bug when multiple arrow keys where pressed and the snake would stop
Removed drawing on canvas from Playground and Snake and added DrawingSurace object for drawing on canvas
Made the food look as in classic snake and adjusted canvas size to support the new grid size
Replaced setTimeout with requestAnimationFrame
Added design for the snake
Added reset.css
Fixed chrome problems with arrow keys
Styled gameover screen