added a notify system for consumers per queue

I don't think you're ever unsubscribing from channels you're no longer in. I think you'll need to make this:

```go
queuesAdded := stringSliceSub(queueNames, lastSubscribedQueues)
queuesRemoved := stringSliceSub(lastSubscribedQueues, queueNames)

if len(queuesAdded) > 0 {
    // subscribe to them
}
if len(queuesRemoved) > 0 {
    // unsubscribe from them
}
```