Import a TransXchange XML file
Value
For a single-service file, a named list of data frames, one per TransXchange section, or NULL if the file contains nothing to convert. For a multi-service file, a `txc_multi` list of such objects.
Details
This function imports the raw transXchange XML files and converts them to a R readable format.
A single TransXchange file may declare several `<Service>` elements (a registration covering, say, the CB2 to CB6 school services as one document). The export path is written around one service per object - it reads `Services_main$...[1]` for the route id, name, agency and mode - so such a file is split into one import result per service and the result carries class `txc_multi`. [transxchange2gtfs()] flattens those back into the list of objects it converts, so each service becomes its own GTFS route.
