Add ability to simulate message traversal

[jakauppila]

It would be great if the application could simulate message traversal across the topology once displayed.

Here's a project that does just that, but does not support headers exchange. I'd find more value in being able to import the definition and then show just that.

http://tryrabbitmq.com
https://github.com/RabbitMQSimulator/RabbitMQSimulator