tor/changes/prop171

  o Major features:
    - You can now configure Tor so that streams from different
      applications are isolated on different circuits, to prevent an
      attacker who sees your streams leaving an exit node from linking
      your sessions to one another.  To do this, choose some way to
      distinguish the applications -- have them connect to different
      SocksPorts, or have one of them use SOCKS4 while the other uses
      SOCKS5, or have them pass different authentication strings to
      the SOCKS proxy.  Then use the new SocksPort syntax to configure
      the degree of isolation you need. This implements Proposal 171.

  o Minor features:
    - There's a new syntax for specifying multiple client ports (such as
      SOCKSPort, TransPort, DNSPort, NATDPort): you can now just declare
      multiple ...Port entries with full addr:port syntax on each.
      The old ...ListenAddress format is still supported, but you can't
      mix it with the new SOCKSPort syntax.

  o Code simplifications and refactoring:
    - Rewrote the listener-selection logic so that parsing which ports
      we want to listen on is now separate form binding to the ports
      we want.