* bugs

- when exactly on turn, distance to next point is still often 50m
    -----> it does not buzz very often on turns

- when going backwards we have a tendencing to get a wrong current_segment

* additional features

- config screen
    - are we on foot (and should use compass)

- we need to buzz 200m before sharp turns (or even better, 30seconds)
(and look at more than next point)

- display distance to next water/toilet ?
- dynamic map rescale
- display scale (100m)

- compress path ?

* misc

- code is becoming messy