2005-03-21 jrandom

    * Fixed the tunnel fragmentation handler to deal with multiple fragments
      in a single message properly (rather than release the buffer into the
      cache after processing the first one) (duh!)
    * Added the batching preprocessor which will bundle together multiple
      small messages inside a single tunnel message by delaying their delivery
      up to .5s, or whenever the pending data will fill a full message,
      whichever comes first.  This is disabled at the moment, since without the
      above bugfix widely deployed, lots and lots of messages would fail.
    * Within each tunnel pool, stick with a randomly selected peer for up to
      .5s before randomizing and selecting again, instead of randomizing the
      pool each time a tunnel is needed.