Add Strasbourg's GTFS

[XioNoX]

Not tested but fits the format.

Source is https://transport.data.gouv.fr/datasets/donnees-theoriques-gtfs-et-temps-reel-siri-lite-du-reseau-cts and should be refreshed after May 12th. URL seems stable.

[dabreegster]

Sorry for taking so long to look at this!

You can reimport by running ./import.sh --raw --map --city=fr/strasbourg. Unfortunately I get an error, because the trips.txt file doesn't have a shape_id column. More generally, there's no shapes.txt file included. It's an optional file that specifies the geometry of each route. The import process requires it; otherwise we'd have to snap / map-match stop pairs to roads. That hasn't been implemented yet.