Added a small and simple test EI.java. and fixed some buggs

src/ei/game/EI.java

@@ -1,5 +1,20 @@
 package ei.game;
 
-public class EI {
+import ei.engine.LWJGLGameWindow;
+import ei.engine.state.GameStateManager;
+import ei.game.gamestate.InGameState;
 
+public class EI extends LWJGLGameWindow{
+	public static void main(String[] args){
+		new EI();
+	}
+
+	public EI() {
+		super("EI");
+	}
+	
+	protected void init(){
+		GameStateManager.getInstance().addState(new InGameState("InGameState"));
+		GameStateManager.getInstance().setActive("InGameState");
+	}
 }

src/ei/game/gamestate/InGameState.java

@@ -0,0 +1,30 @@
+package ei.game.gamestate;
+
+import ei.engine.scene.Node;
+import ei.engine.scene.Sprite;
+import ei.engine.state.GameState;
+
+
+public class InGameState extends GameState{
+	private Node rootNode;
+	private Sprite s1;
+	
+	public InGameState(String name){
+		super(name);
+		rootNode = new Node("InGameNode");
+		s1 = new Sprite("tank","data/units/tank.png");
+		rootNode.add(s1);
+		s1.setLocation(1, 1);
+	}
+	
+	@Override
+	public void render() {
+		rootNode.render();
+	}
+
+	@Override
+	public void update() {
+		s1.getLocation().add(1);
+	}
+
+}