Feature: populate NX2 waypoints from GPX

[lkarsten]

Inputing waypoints into the NX2 race computer through Nexus Race is painful and slow.

It should be possible to supply a GPX file (or similar) and have it translated into FDX and sent over the bus.

Prerequisite for this to understand the configuration format used. Read before talking, walk before running and all that.

Sample dumps like dumps/set1_*.dump and dumps/set2_*.dump did for wind speed/direction will be required. Small dumps that: 1) reset/delete a waypoint using Nexus Race, 2) insert a waypoint number n at a known position.

GPX and formatting the FDX message will be trivial when we know how.

Currently blocked on more data. Input welcome.