another large series of changes, related to the refactoring.

CompoundShapes are tricky to manage with respect to persistent contact points and swapped order of btCollisionObjects,
During dispatch, finding an algorith etc. order can be swapped.
fixed several other issues, related to SimpleBroadphase (removing a proxy was not working)

Demos/ColladaDemo/ColladaDemo.cpp

@@ -100,7 +100,7 @@ class MyColladaConverter : public ColladaConverter
 
 	virtual	void	setGravity(const btVector3& grav)
 	{
-		m_demoApp->setGravity(grav);
+		m_demoApp->getDynamicsWorld()->setGravity(grav);
 	}
 	virtual void	setCameraInfo(const btVector3& camUp,int forwardAxis) 
 	{