Status > keep cancelled trips & skipped stop time from GTFS-RT Trip Updates

[mmathieum]

GTFS Real Time trip update can make a trip cancelled or a stop time skipped, these are currently removed from the data since the main app UI cannot yet handle cancelled Schedule.Timestamp.

• update ScheduleStatusFilter to add "include cancelled timestamp" boolean (default false)
• update Schedule.Timestamp to add cancelled boolean (default false)
• in GTFSRealTimeTripUpdatesProviderExt. if the new filter boolean is true, keep the schedule timestamp instead of removing it and update it's "cancelled" boolean value to true.
• do check for tripUpdate.trip.scheduleRelationship as CANCELLED (ignore DELETED since it means transit agency wants to hide trip( as well as stopTimeUpdate.scheduleRelationship` as SKIPPED
• add unit test to cover for these new use cases (filter boolean and cancelled boolean(

UI change will be made in: mtransitapps/mtransit-for-android#163

Links:

• https://gtfs.org/documentation/realtime/feed-entities/trip-updates/
• https://gtfs.org/documentation/realtime/reference/#message-stoptimeupdate