* Include SSU establishment failure in the peer profile as a commError,
      as we do for TCP establishment failures.
    * Don't throttle the initial transmission of a message because of ongoing
      retransmissions to a peer, since the initial transmission of a message
      is more valuable than a retransmission (since it has less latency).
    * Cleaned up links to SusiDNS and I2PTunnel (thanks zzz!)