Audit Mode Formatter Integration

@mcquin 

Right now I only have the STDOUT formatter tied into the event bus.  I'm going to add the JSON formatter and update this review, but I wanted to get it started.
using 'controls' to group multiple controls at the outmost level and 'control' to group multiple controls anywhere inside that is going to be confusing to the user.  we should pick one and be consistent, even though we know that they're different things (one a DSL method on chef, the other an rspec method), the users shouldn't have to care about the implementation details.