Directories within own tracks

[geronimoge]

Since I'm working with tracks a lot, they're getting more and more. For a better organization it would be very helpful if I could work with (sub)directories.

• when importing tracks
• when choosing tracks within the app

E.g.:

• My walks (directory) ** Canada (subdirectory) *** track 1.gpx *** track 2.gpx ** Norway (directory) *** Vacation 1 (subdirectory) **** track 1.gpx
• Walks from travel books (directory) ** Italy (subdirectory) *** track 1.gpx *** track 2.gpx *** track 3.gpx ** Barcelona (subdirectory) *** track 1.gpx
• Others (directory) ** track 1.gpx ** track 2.gpx ** track 3.gpx ** track 4.gpx