message: Added fature announcement for caller_identification and publisher_identification.
diff: @@ -1105,10 +1105,21 @@ std::future<void> wamp_session::hello(client_credentials cc)
  auto initiate_cb = [this, cc]()
  {
  +
  json_object roles ({
  - {"publisher", json_object()},
  + {"publisher", json_object({
  + {"features", {json_object({
  + {"publisher_identification", true}
  + })
  + }}
  + })},
  {"subscriber", json_object()},
  - {"caller", json_object()},
  + {"caller", json_object({
  + {"features", json_object({
  + {"caller_identification", true}
  + })
  + }
  + })},
  {"callee", json_object()}
  });
  