Type hierarchy

Arrange the class inheritance based on this hierarchy.

Things turned out well. I had to resize the physics body for the Player sprite to make it 20 pixels shorter in order to keep the sprite on the ground. That appeared to be the only unexpected change.

There is a Config type that is used to instantiate the various Phaser.Physics.Arcade.Sprite classes. The creation of the sprites for a scene is greatly standardized. Previous haphazardly-assigned properties will probably end up in the classes.