list both stations and platforms in the GTFS output

[miklcct]

The stops.txt generated in the GTFS now only lists the train stations with an empty location_type field without the platform definitions, and doesn't distinguish between different part of the station (such as St Pancras high and low levels).

This makes the generated output useless for given step-by-step directions to access the platform in order to take trains, or to provide directions to transfer between trains within a complex station.

As the source data contains the platform information, it should be possible to do it properly in the GTFS file, by listing all stations with location_type = 1 and all platforms with location_type = 0, and referencing the appropriate platform from the trips, such that if we can match the coordinates of the platforms from OpenStreetMap, we can provide routing to the level that how the passenger can access the platform from the train station and how should the passenger change between trains, and to guide them to the lifts for step-free access.

[linusnorton]

I'm not actively maintaining this beyond CVEs at the moment but I would be happy to accept a pull request