track all lines seen and all lines said by Markov. every 30 seconds,
if there have been more than 20 such lines, and Markov is responsible
for roughly half of them, then shut up for 30 seconds, because the
bot probably got stuck talking to another bot.
this should mean that such a reply infinite loop can't happen for
more than a minute.
i'm not entirely sure on the 30 sec/20 lines ratio. this may need
tuning.