Agents process checkAgents() would be improved if it took place in an interruptible background daemon thread

It's now challenging to shut down the agents process because the checkAgents() method is called directly from runAgents(). That means that there can be an extended period of time before the agents process realizes that it needs to shut down and acts accordingly. It would be much better to run the checkAgents() code in a daemon thread that can be kicked with an interrupt and thus shut down quickly.