Avoid EventEmitter memory leak warnings

This isn't too bad but when you call consume() on an exchange with at least 10 other consumers, you will receive the following Node warning:

```
(node) warning: possible EventEmitter memory leak detected. 11 ready listeners added. Use emitter.setMaxListeners() to increase limit.
Trace
at EventEmitter.addListener (events.js:239:17)
at EventEmitter.once (events.js:265:8)
at EventEmitter.createQueue [as queue] (/var/www/sites/ms-kegactivity-receiver/node_modules/jackrabbit/lib/exchange.js:84:15)
```

It'd be nice to be able to suppress this on the exchange's instance of EventEmitter (you can do it globally but that's not a great solution IMO). I'd also be down with a "suppressWarnings" option somewhere.