* New tunnel build process - does not use the new crypto or new peer
      selection strategies.  However, it does drop the fallback tunnel
      procedure, except for tunnels who are configured to allow them, or for
      the exploratory pool during bootstrapping or after a catastrophic
      failure.  This new process prefers to fail rather than use too-short
      tunnels, so while it can do some pretty aggressive tunnel rebuilding,
      it may expose more tunnel failures to the user.
    * Always prefer normal tunnels to fallback tunnels.
    * Potential fix for a bug while changing i2cp settings on I2PSnark (thanks
      bar!)
    * Do all of the netDb entry writing in a separate thread, avoiding
      duplicates and batching them up.