Bug fixes to Interactable

1. Interactable no longer requires a coordinate.
2. Interactable now properly checks mouse coordinates.
Renamed Map to MapClass
Added function to subtract two Points

1. For dx/dy helping in Pawn.
Added placeholder screen point to Coordinate

1. Placeholder because eventually the map won't start at (0,0).
Lots of refactoring to Pawn.

1. Still needs lots of polishing to the pathfinding, however.
Initial refactoring of Customer
Bug fixes to State