Yet another refactoring. I am getting rid of the new Entity2D class.

Note that the original Entity class will become the Entity2D class.
I removed the class Entity2D class.
I refactored the entity class. Now the base entity class is Entity2D and this class is extended by both the EntityImage and EntityShape.

One thing to note. Consider making the Entity2D class abstract to the developer is forced to create an instance of either the EntityImage or EntityShape classes.