Starting to travel, so limited time today.

Yet Another Thread added to the assistant, all it does is watch for changes
to transfer information files, and update the assistant's map of transfers
currently in progress. Now the assistant will know if some other repository
has connected to the local repo and is sending or receiving a file's
content.

This seemed really simple to write, it's just 78 lines of code. It worked
100% correctly the first time. :) But it's only so easy because I've got
this shiny new inotify hammer that I keep finding places to use in the
assistant.

Also, the new thread does some things that caused a similar thread (the
merger thread) to go into a MVar deadlock. Luckily, I spent much of 
[day 19](day_19__random_improvements) investigating and fixing that
deadlock, even though it was not a problem at the time.

So, good.. I'm doing things right and getting to a place where rather
nontrivial features can be added easily.

--

Next up: Enough nonsense with tracking transfers... Time to start actually
transferring content around!
