GTFS Directions experimental support

[mmathieum]

• route_directions.txt #RTCS
  • route_id
  • direction_id
  • route_direction_name
• directions.txt #STLevis
  • route_id
  • direction_id
  • direction_name
  • ...
• directions.txt #Trillium #Banff #Juneau #RiverCities
  • route_id
  • direction_id
  • direction
• trips.txt #DRT
  • route_id
  • trip_id
  • direction_name
  • ...

Links:

• [Public] GTFS-DirectionNames
• https://github.com/google/transit/issues/228
• https://trilliumtransit.com/gtfs/reference/#directions