model of waiting for state changes. Before we were watching the database
(which means we can only watch for terminal/stable/long-lived states, and
have to poll the db). Now things that are waiting for states to change
become event listeners, and watch the stream of events flow by, and don't
have to do any polling. They can now watch for any state, and even
sequences of states (ie a Shutdown followed by an Isup).

To do this, there is now a cool StateWait.pm library that encapsulates the
functionality needed. To use it, you call initStateWait before you start
the chain of events (ie before you call node reboot). Then do your stuff,
and call waitForState() when you're ready to wait. It can be told to
return periodically with the results so far, and you can cancel waiting
for things. An example program called waitForState is in
testbed/event/stated/ , and can also be used nicely as a command line tool
that wraps up the library functional...