Hardkoking av perry

Erstattet alt innhold i GameState, Pong og Ball (nyopprettet).
Kjører.
Ball classed remove

Ball is now a Sprite, so the Ball class was redundant.
Tidied up in the backgroud drawing.

Changed the the code for drawing the background and made it black.
Changed paddle and ball images
Changed handling of paddle images

Removed the two old variables for storing paddle images and added one
for both (since they now use the same image).
Changes to canvas var name and text position

Changed the vanriable name for the canvas from can to canvas.
Changed the position of the score text.
Changed the handling of the text-type variable (made it a global
variable instead of two local ones).
Tidied up the code
Refactored handling of wall collision
Changed variable names for scores