Added support for MQTT (#765)

Added support for MQTT with the existing events and messages.
To listen with mqtt simply change api.listen to api.listenMqtt

DOCS.md

@@ -25,6 +25,7 @@
 * [`api.getUserInfo`](#getUserInfo)
 * [`api.handleMessageRequest`](#handleMessageRequest)
 * [`api.listen`](#listen)
+* [`api.listenMqtt`](#listenMqtt)
 * [`api.logout`](#logout)
 * [`api.markAsRead`](#markAsRead)
 * [`api.markAsReadAll`](#markAsReadAll)
@@ -1308,6 +1309,22 @@ login({appState: JSON.parse(fs.readFileSync('appstate.json', 'utf8'))}, (err, ap
 
 ---------------------------------------
 
+<a name="listenMqtt"></a>
+### api.listenMqtt(callback) (Experimental)
+Same as [`api.listen`](#listen) but uses MQTT to recieve data.
+
+Will call `callback` when a new message is received on this account.
+By default this won't receive events (joining/leaving a chat, title change etc...) but it can be activated with `api.setOptions({listenEvents: true})`.  This will by default ignore messages sent by the current account, you can enable listening to your own messages with `api.setOptions({selfListen: true})`. This returns `stopListening` that will stop the `listen` loop and is guaranteed to prevent any future calls to the callback given to `listenMqtt`. An immediate call to `stopListening` when an error occurs will prevent the listen function to continue.
+
+
+__Arguments__
+
+- `callback(error, message)`: A callback called every time the logged-in account receives a new message.
+
+Messages and Events are the same as [`api.listen`](#listen)
+
+---------------------------------------
+
 <a name="logout"></a>
 ### api.logout([callback])
 

index.js

@@ -99,6 +99,7 @@ function buildAPI(globalOptions, html, jar) {
     'getUserInfo',
     'handleMessageRequest',
     'listen',
+    'listenMqtt',
     'logout',
     'markAsRead',
     'markAsReadAll',