Revising source and project values
Refactor payload class to prepare for a ReceivePayload
Switch receive hook to the git endpoint

The git endpoint eliminates some limitations of the team_inbox endpoint but introduces other limitations.  I have contacted the Flowdock team to see if they are agreeable to some changes to the git endpoint which will make it more useful for every consumer of the git endpoint.
Use the standard Ticket Notifier to generate flow events