provide interface for setting the number of tasks (unused in the btDiscreteDynamicsWorld).

src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.h

@@ -150,6 +150,9 @@ public:
 	///apply gravity, call this once per timestep
 	virtual void	applyGravity();
 
+	virtual void	setNumTasks(int numTasks)
+	{
+	}
 
 };