Optimizing step 1

As it is, the server has to serve up a request for every IM-ing user every second in order to poll for new messages. Ideally, I'd like to open a socket that stays open, and hopefully some day we'll be there.

There will be other forays into optimizing, but for now, a good thing to do would be to avoid a full-on Drupal bootstrap when polling. It basically only need database access, and fortunately that's pretty high in the bootstrap order of event .. so make a light weight bootstrap to use for polling for messages.