message: Correction of array name to receive attachments
  The array to obtain the Attached files is message.data.files not message.original_message.files
diff: @@ -166,14 +166,14 @@ bot.reply(message,{text: 'I made this file for you.', files:[fs.createReadStream
  ## Receiving files
  -Your bot may receive messages with files attached. Attached files will appear in an array called `message.original_message.files`.
  +Your bot may receive messages with files attached. Attached files will appear in an array called `message.data.files`.
  Botkit provides 2 methods for retrieving information about the file.
  ### bot.retrieveFileInfo(url, cb)
  | Parameter | Description
  |--- |---
  -| url | url of file from message.original_message.files
  +| url | url of file from message.data.files
  | cb | callback function in the form function(err, file_info)
  The callback function will receive an object with fields like `filename`, `content-type`, and `content-length`.
  @@ -181,8 +181,8 @@ The callback function will receive an object with fields like `filename`, `conte
  ~~~ javascript
  controller.on('direct_message', function(bot, message) {
  bot.reply(message, 'I got your private message. You said, "' + message.text + '"');
  - if (message.original_message.files) {
  - bot.retrieveFileInfo(message.original_message.files[0], function(err, file_info) {
  + if (message.data.files) {
  + bot.retrieveFileInfo(message.data.files[0], function(err, file_info) {
  bot.reply(message,'I also got an attached file called ' + file_info.filename);
  });
  }
  @@ -192,7 +192,7 @@ controller.on('direct_message', function(bot, message) {
  ### bot.retrieveFile(url, cb)
  | Parameter | Description
  |--- |---
  -| url | url of file from message.original_message.files
  +| url | url of file from message.data.files
  | cb | callback function in the form function(err, file_content)
  The callback function will receive the full content of the file.
  @@ -200,10 +200,10 @@ The callback function will receive the full content of the file.
  ~~~ javascript
  controller.on('direct_message', function(bot, message) {
  bot.reply(message, 'I got your private message. You said, "' + message.text + '"');
  - if (message.original_message.files) {
  - bot.retrieveFileInfo(message.original_message.files[0], function(err, file_info) {
  + if (message.data.files) {
  + bot.retrieveFileInfo(message.data.files[0], function(err, file_info) {
  if (file_info['content-type'] == 'text/plain') {
  - bot.retrieveFile(message.original_message.files[0], function(err, file) {
  + bot.retrieveFile(message.data.files[0], function(err, file) {
  bot.reply(message,'I got a text file with the following content: ' + file);
  });
  }
  