Document requirements for queue name

Also, fix the example. It didn't work against ActiveMQ, for which a
queue named 'foo' is considered to be the same as '/queue/foo', which is
fine, except that when the MESSAGE comes back on the queue, it uses the
fully-qualified destination, and stomp-client won't find a subscription
callback for that destination, so no messages were ever being printed.
Remove a note and extraneous whitespace
Note that disconnect event can also be involuntary
Emit parse errors as an` 'error' event

Failing to parse a received frame is fatal, and an 'error' event is
emitted and the connection destroyed. Error objects may have a .details
property.
Export the StompClient constructor from require

Its the only (useable) export, and simplifies usage.