Merged hotfix/queue_callback_error into master

src/queue.ts

@@ -20,7 +20,7 @@ class Queue {
     let action = this._queue.shift();
     if (action) {
       this._running = true;
-      new Promise((reject, resolve) => action(resolve)).then(this._next)
+      new Promise((resolve, reject) => action(resolve)).then(this._next.bind(this));
       // action(() => {
       //   this._next();
       // });