Made each projectile aware of which tank that fired it. Also added preliminary collision handling for projectiles.
World now has a size
Added MapBounds class
New worlds now adds a MapBounds automatically
Made the tank bounce when it hits the edge of the map.
Projectiles are removed if they hit the edge of the map.
Projectiles now destroy themselves
Removed old code for removing and destroying projectiles
Projectiles now remove themselves from their Tank's list of projectiles when they get destroyed
DefaultProjectile now has a shape of a rectangle
Proper merge, hopefully..