Added parallax scrolling.

Added background image.
Moved the player forward some pixels.
Added player frames.

Added animation for player.
Changed X position of player.
Now scores a point when the player crosses a gate (previously was when
the gate reached the end of the screen)
Scrolling background and animated frames now stop when pausing the game.
Merge pull request #1 from hi-ban/master

Added parallax scrolling. Added player frames.