WIP - Implementation of a static ground model.
WIP early eimplementation of the ground
WIP Working implementation of a cube ground with gravity.
WIP Tweaking parameters for gravity and models.
Merge branch 'worldphysics' into world-scene

Conflicts:
	src/renderer/Model.java
	src/renderer/ModelFactory.java
	src/threed/space/shooter/Main.java
Reverting protected keyword to private.
Removing loadGround call from ModelFactory and moving the logic to Main.
Merge pull request #10 from jtmzheng/world-scene

Adding a ground + some gravity.