[WIP] Audit mode specs

@tyler-ball Here's my work so far on unit tests for audit mode (I have another big file in flight, should be done tomorrow AM). What do you think so far?

\cc @sersut 
The ResourceReporter and the AuditReporter should receive `#run_failed` relayed via the `@events` proxy [here](https://github.com/opscode/chef/blob/audit-mode/lib/chef/client.rb#L478) - are you not seeing that?