Comment on doc.gpx naming
TODO update
Page visibility + screen lock note
Hide settings, fixes to About page
Battery saving tip, remove alarm note license
TODO update
Make trailsegment elems/fix a constant
Incremental trail segment 2d/3d length calculation

This allows length to be efficiently updated in realtime.
Incremental trail length updating, per fix
TODO update
Average speed for current segment
TODO update
Clear trail fix for avg spd