Fixed depth issues, started basic input controls

...gvengine.core.Input
+ Input - will eventually manage input from a variety of input
mechanisms
+ InputBinding - used to represent a command bound to an input device
+ InputBindingMode - KEYBOARD, MOUSE, or CONTROLLER

...gvengine.tests
+ControllerTest - a simple test so I could find out which buttons do
what, and how I receive input
>ChunkTest - changed glEnable( GL_DEPTH ) to glEnable( GL_DEPTH_TEST );

Made various other small changes that do not affect the engine itself (I
think).