Fixing zmq transport to work with latest version of seneca transport

ZMQ issues addressed in this pull request:
- https://github.com/rjrodger/seneca-zmq-transport/blob/master/zmq-transport.js#L40-L41 should listen for type 'zmq' as pubsub is legacy
- https://github.com/rjrodger/seneca-zmq-transport/blob/master/zmq-transport.js#L179-L255 needed updating to work with latest version of seneca transport

It would also be good if you could publish seneca-zmq-transport once the pull request has been merged and you're happy with the changes :)