Added header comment
Added comments to RoadPoints.py
added comments to the settings.py file
New vehicles cannot be added after simulation has begun
Vehicle objects no longer have a sprite object. Instead, they inherit from the Layer class.
Vehicle objects are now inherited from Layer objects, which allows us to add the sprite and the label directly to the layer. This allows for the label to follow the car no matter where it travels
Vehicle labels are no longer explicitly needed to instantiate