code: function enqueue(){
  		var tasks = argumentFilter(arguments);
  		queued.push({ tasks:tasks });
  		// Timeout needed to increment expected, if next item exists.
  		// If it run without timeout, expected always be 0 and the functions
  		// will be executed immediately obtaining undefined as parameter.
  		setTimeout(function(){if (! expected) runQueue();},1);
  		return enqueue;
  	}
docs: Add a new group of tasks in stack.