Added depth to the signs.

- Need to figure out how to run collision testing for multiple
  objects.
Added a message box that appears when sign1 is interacted with.

- Pressing interact key (A right now) checks if lucas is colliding
  with an object and if he is, it calls that objects interact method.
  This is a problem since lucas still only collide with one hard-coded
  object.
- Changed the collide function to support interactivity.