2005-12-13 zzz

    * Don't test tunnels expiring within 90 seconds
    * Defer Test Tunnel jobs if job lag too large
    * Use JobQueue.getMaxLag() rather than the jobQueue.jobLag stat to measure
      job lag for tunnel build backoff, allowing for more agile handling
      (since the stat is only updated once a minute)
    * Use tunnel length override if all tunnels are expiring within one
      minute.