Description:
------------
RabbitMQ ignores the RoutingKey altogether when binding the queue to an exchange 
of type FANOUT

http://www.rabbitmq.com/tutorials/amqp-concepts.html#exchange-fanout

It would be great to have the $routingKey parameter made optional instead of 
having to type "foobar" or "ignored".

The broker, being used (RabbitMQ, other) should then handle pre-conditions to 
make the bind() effective.

---
From manual page: http://www.php.net/amqpqueue.bind
---


Test script:
---------------
$ex = new AMQPExchange($ch);
$ex->declare('exchange1', AMQP_EX_TYPE_FANOUT);

// Create a new queue
$q = new AMQPQueue($ch);
$q->declare('queue1');

// Bind it on the exchange to routing.key
$ex->bind('queue1');

Expected result:
----------------
Queue is bound to exchange.

Actual result:
--------------
Uncaught exception 'AMQPExchangeException' with message 'Could not bind exchange. 
No routing key given.'