Add thread to queue

def add_thread(self, checker, end_callback, source_code, parent):
        """Add thread to queue"""
        parent_id = id(parent)
        thread = AnalysisThread(self, checker, source_code)
        self.end_callbacks[id(thread)] = end_callback
        self.pending_threads.append((thread, parent_id))
        logger.debug("Added thread %r to queue" % thread)
        QTimer.singleShot(50, self.update_queue)