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)

src/BulletDynamics/Dynamics/btDynamicsWorld.h

@@ -38,7 +38,7 @@ class btDynamicsWorld : public btCollisionWorld
 		}
 		
 		///stepSimulation proceeds the simulation over timeStep units
-		virtual void	stepSimulation( float timeStep) = 0;
+		virtual void	stepSimulation( float timeStep,int numSubsteps=1) = 0;
 				
 		virtual void	updateAabbs() = 0;
 				
@@ -50,6 +50,12 @@ class btDynamicsWorld : public btCollisionWorld
 
 		virtual btIDebugDraw*	getDebugDrawer() = 0;
 
+		//once a rigidbody is added to the dynamics world, it will get this gravity assigned
+		//existing rigidbodies in the world get gravity assigned too, during this method
+		virtual void	setGravity(const btVector3& gravity) = 0;
+
+		virtual void	addRigidBody(btRigidBody* body) = 0;
+
 };
 
 #endif //BT_DYNAMICS_WORLD_H