Consumer test helper

@joshuafleck  This adds the facility to test the consumer routes without Rabbit as we talked about yesterday.

@dcoxall @ngsmrk just as you are on my track :)


I prefer the Ruby formatting - You've already called out 

> include the module `TestHelpers` in your tests and then invoke `rabbit_feed_consumer.consume_event(event)`. Following is an example

This makes me think the highlighting is not that critical.