Committing a new Class Diagram
Class Diagram represents a "completed subset" of the engine and game
components. Additions will be made a point of code completeness.

Other changes:
Changed all references to "takeInput()" from public to protected. 
Added an alternative GameContainerScene called GameContainerScene_Demo -
this shall be used as the proof of concept for the game. We will be able
to reuse this as an actual demo scene.

Other miscellaneous changes...