def listen_queues(queues) #:nodoc:
      @listened_queues = queues
      @exchanges_for_queues = exchanges_for_queues(queues)
      EM.run do
        each_server do
          connect_server connection_settings
        end
        yield if block_given?
      end
    end
def listen_queues(queues) #:nodoc:
      @listened_queues = queues
      @exchanges_for_queues = exchanges_for_queues(queues)
      EM.run do
        each_server do
          connect_server connection_settings
        end
        yield if block_given?
      end
    end
create a new subscriber instance
 the client calls this method to subscribe to a list of queues.
 this method does the following things:

 * creates all exchanges which have been registered for the given queues
 * creates and binds each listed queue queues
 * subscribes the handlers for all these queues

 yields before entering the eventmachine loop (if a block was given)