this keeps us from having the entire markov chain in memory and
having to do the pickling and so on. in many ways, this is a good
thing.
in one way, this is a bad thing. each line on irc will create a
__start1,__start2 item in the database, which means starting a
chain will be an expensive process. (approx 3 seconds, from irc
logs of 600,000 K lines). following selects run much faster, but
the first one is dog slow. a later commit should hopefully fix this.
Brian S. Stephan
1712a7db53