First pass at functioning app

This adds handling for 'review' and 'award' webhook events.  In the case of 'review', the app will call back to BadgeKit API to award the badge immediately if the review was approved.

The following hatchet messages are sent:

'application_denied'
'application_approved'
'badge_awarded'

Note that in the case of an approved application, both an 'application_approved' and a 'badge_awarded' message will be sent.