rem: fManager->delete_interface(this);  CalculateMRU();
add: Delete();
context: PPPInterface::RemoveChild(PPPInterface *child){	LockerHelper locker(fLock);		if(!fChildren.RemoveItem(child))		return false;		child->SetParent(NULL);		// parents cannot exist without their children	if(CountChildren() == 0 && fManager && Ifnet())		fManager->delete_interface(this);		CalculateMRU();		return true;}