Changed Screens to load via IEnumerable
Removed default systems from Screen
Added behavioral hooks for GameObject
Moved Movement behavior up into component
Removed sprite rendering system

Moved rendering behavior up into SpriteComponent
Moved screen wrapping up into component

Also removed ScreenWrappingSystem
Removed UISystem and BackgroundRenderingSystem

Moved functionality into game components.
Remove GameSystem, Add GameViews
Change screens to states
Added complete Scene Graph
TODO comments for future refactors
Fixing of type-casting in AddListener
Made View init less brittle
Changed button rendering to scene graph
Finished moving all rendering to SceneGraph
Moved pointer "picking" into SceneGraph
Save TODO comments
Moved SpriteBatch for Nodes into SceneGraph

Will allow camera transforms (like shakes) in a central location in the future.
Removed unused sorting code
Removed last "system" and split into input handlers