Added nyc_subway_stop_routes_df, a long-form mapping from each parent subway station to the GTFS routes that call at it.
Added nyc_subway_complexes_df and nyc_subway_complexes_sf, with one row per MTA station complex and (in the sf version) the centroid geometry of the constituent parent stops.
Added nyc_subway_complex_stops_df, the long-form bridge between MTA station_complex_id and GTFS parent stop_id.
Added nyc_subway_complex_routes_df, the flat join giving the routes that serve each MTA station complex. Lets downstream code drop ad-hoc parsing of route bullets from the station_complex text in nycsubwayhourly.