Some routes have titles that include characters which are illegal on certain filesystems. This release replaces common illegal characters with an underscore.

Certain tracks, such as https://www.sac-cas.ch/en/huts-and-tours/sac-route-portal/marchhorn-1115/ski-touring/discesa-lungo-il-canalone-del-marchhorn-5976/, do not have a departure point. This release can handle that case as well now.

Don't crash if segments.geom is null.

Sometimes (for example https://www.sac-cas.ch/it/capanne-e-escursioni/portale-escursionistico-del-cas/albristhubel-6246/escursioni-con-le-racchette/von-matten-simmental-2785/) segments.geom is null and the creation of the gpx xml subsequently fails.

If that is the case just ignore it and do not try to turn it into a track segment.

Thanks to wizche for the report and fix!

- use correct track title

- add all waypoints & the endpoint
- do not use the book number if there is none

- add all route segments to gpx file

- only activate the icon if the selected track could be parsed correctly

- Start and destination points are saved as waypoints in the gpx file.