Only try to match updates to a trip if it is not a cancellation
Store the stopIndex in TransitBoardAlight, instead of the hopIndex.
Move boarding/updating/wheelchair restrictions into TripTimes

so that it may be updated using realtime information
Add GTFS-rt+HTTP support for StopTime updating
Replace UpdateBlock with TripUpdate

A TripUpdate may contain in addition to the stop specific updates,
trip specific changes (add a new trip, cancel the trip, ...)