Update README.md after breaking change

Hi.

I'm using your module. Thanks!

Alas, I had some minor issues figuring out how to use it.

You instruct the user to inject a vertxEventBus object in the controller, but a few lines below you demonstrate how to send/publish/receive messages using a vertxEventBus **Service**.

Furthermore, it seems the third boolean parameter from the vertxEventBusService.send method has been removed quite some time ago as you fixed #19