Start re-organizing demos so the physics setup can be shared easier (explicit create graphics objects, init/exit physics etc)

Add B3G_RETURN key code, only implemented in Windows so far (todo: Mac, Linux)
Fix Windows key management (use WM_CHAR event instead of WM_KEYUP
Add Return (OnKeyReturn) key support TreeNode, so we can select an item using the return key.

Demos/CommonPhysicsSetup.h

@@ -0,0 +1,53 @@
+
+#ifndef COMMON_PHYSICS_SETUP_H
+#define COMMON_PHYSICS_SETUP_H
+
+class btRigidBody;
+class btBoxShape;
+class btTransform;
+class btCollisionShape;
+#include "LinearMath/btVector3.h"
+class btDiscreteDynamicsWorld;
+
+///The GraphicsPhysicsBridge let's the graphics engine create graphics representation and synchronize
+struct GraphicsPhysicsBridge
+{
+	virtual void createRigidBodyGraphicsObject(btRigidBody* body,const btVector3& color)
+	{
+	}
+	virtual void createCollisionShapeGraphicsObject(btCollisionShape* collisionShape)
+	{
+	}
+	virtual void syncPhysicsToGraphics(const btDiscreteDynamicsWorld* rbWorld)
+	{
+	}
+};
+
+struct CommonPhysicsSetup
+{
+public:
+
+	virtual ~CommonPhysicsSetup() {}
+	
+	virtual void initPhysics(GraphicsPhysicsBridge& gfxBridge) = 0;
+	
+	virtual void exitPhysics()=0;
+	
+	virtual void stepSimulation(float deltaTime)=0;
+	
+	virtual bool pickBody(const btVector3& rayFromWorld, const btVector3& rayToWorld) = 0;
+	virtual bool movePickedBody(const btVector3& rayFromWorld, const btVector3& rayToWorld)=0;
+	virtual void removePickingConstraint() = 0;
+
+	virtual void syncPhysicsToGraphics(GraphicsPhysicsBridge& gfxBridge) = 0;
+
+	virtual btRigidBody*	createRigidBody(float mass, const btTransform& startTransform,btCollisionShape* shape, const btVector4& color=btVector4(1,0,0,1))=0;
+	
+	virtual btBoxShape* createBoxShape(const btVector3& halfExtents)=0;
+};
+
+
+
+#endif //COMMON_PHYSICS_SETUP_H
+
+