message: Send a default messaging_type if it's not already specified
diff: @@ -72,6 +72,8 @@ function Facebookbot(configuration) {
  if (message.messaging_type) {
  platform_message.messaging_type = message.messaging_type;
  + } else {
  + platform_message.messaging_type = "RESPONSE";
  }
  if (message.sticker_id) {
  