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.

Demos3/bullet2/RagdollDemo/RagdollDemo.cpp

@@ -343,17 +343,6 @@ public:
 
 
 
-RagDollDemo::RagDollDemo(SimpleOpenGL3App* app)
-:BasicDemo(app)
-{
-	
-}
-RagDollDemo::~RagDollDemo()
-{
-	
-}
-
-
 
 
 void	RagDollDemo::initPhysics()