2005-07-31 jrandom

    * Adjust the netDb search and store per peer timeouts to match the average
      measured per peer success times, rather than huge fixed values.
    * Optimized and reverified the netDb peer selection / retrieval process
      within the kbuckets.
    * Drop TCP connections that don't have any useful activity in 10 minutes.
    * If i2np.udp.fixedPort=true, never change the externally published port,
      even if we are autodetecting the IP address.
(also includes most of the new peer/NAT testing, but thats not used atm)