message: Default message to markdown
  Add handler for missing user
diff: @@ -323,9 +323,18 @@ function Sparkbot(configuration) {
  */
  bot.startPrivateConversation = function(message, cb) {
  - botkit.startTask(bot, {
  - toPersonEmail: message.user
  - }, function(task, convo) {
  + var message_options = {};
  +
  + // if a user is specified, use that -- this happens when a user says something
  + // otherwise, use the actorId - this might happen when a user takes an action
  + // for example, if a user adds a bot to the channel...
  + if (message.user) {
  + message_options.toPersonEmail = message.user;
  + } else if (message.original_message.actorId) {
  + message_options.toPersonId = message.original_message.actorId;
  + }
  +
  + botkit.startTask(bot, message_options, function(task, convo) {
  convo.on('sent', function(sent_message) {
  // update this convo so that future messages will match
  // since the source message did not have this info in it.
  @@ -348,6 +357,11 @@ function Sparkbot(configuration) {
  ciscospark_message.roomId = message.channel;
  delete ciscospark_message.channel;
  + // default the markdown field to be the same as text.
  + if (ciscospark_message.text && !ciscospark_message.markdown) {
  + ciscospark_message.markdown = ciscospark_message.text;
  + }
  +
  controller.api.messages.create(ciscospark_message).then(function(message) {
  if (cb) cb(null, message);
  }).catch(function(err) {
  