Add method to get collision Tiles from Map

Also add Rectangle class, used in this new method.

Finished Episode 13.1.
Add methods to make Player's collision Rectangles

Finished Episode 13.2.
Add Player collision with wall tiles

Finished Episode 13.3.
Fix max speed in the x direction
Refine and clean up Player movement

Use constants gotten from the original Cave Story. Allows us to
remove the Jump class and to have smoother movement.

Finished Episode 14.