AMQConnection missing "/" for non-default virtual hosts

Hi,

In AMQConnection, line 865, if the virtualHost, is _not_ the default, the resultant toString looks something like this:

```
amqp://guest@192.168.80.3:5672test
```

It should be

```
amqp://guest@192.168.80.3:5672/test
```

PR coming shortly.

-=david=-
