Fix bugs in IPv6 address handling.

  o Currently, address chooser always returns ip4 address for tcpX protocols.
    E.g., A server returns ip4 address even with -veyron.tcp.protocol=tcp6,
    and so a client can't connect a server with that address.

  o Fix a bug in GetIPRoutes() which doesn't return correct default
    routes for IPv6.
  o Updated the benchmark RESULTS.txt and spreadsheet with a new
    results.
    Now the performance of WS are 2 ~ 30% slower than TCP, although
    there are a few noisy results with tiny payloads.

  I added some comments on what I'm not sure about.

Change-Id: I1e350fdf236be9c317cbf959030a68119b37723e
1 file changed