2005-04-28 jrandom

    * More fixes for the I2PTunnel "other" interface handling (thanks nelgin!)
    * Add back the code to handle bids from multiple transports (though there
      is still only one transport enabled by default)
    * Adjust the router's queueing of outbound client messages when under
      heavy load by running the preparatory job in the client's I2CP handler
      thread, thereby blocking additional outbound messages when the router is
      hosed.
    * No need to validate or persist a netDb entry if we already have it
And for some udp stuff:
* only bid on what we know (duh)
* reduceed the queue size in the UDPSender itself, so that ACKs go
  through more quickly, leaving the payload messages to queue up in
  the outbound fragment scheduler
* rather than /= 2 on congestion, /= 2/3 (still AIMD, but less drastic)
* adjust the fragment selector so a wsiz throttle won't force extra
  volleys
* mark congestion when it occurs, not after the message has been
  ACKed
* when doing a round robin over the active messages, move on to the
  next after a full volley, not after each packet (causing less "fair"
  performance but better latency)
* reduced the lock contention in the inboundMessageFragments by
  moving the ack and complete queues to the ACKSender and
  MessageReceiver respectively (each of which have their own
  threads)
* prefer new and existing UDP sessions to new TCP sessions, but
  prefer existing TCP sessions to new UDP sessions