Gauge for evaluating takeoffs & landings, and to show waypoint information.
During a landing approach, the gauge shows information about AGL & vertical speed;
after touchdown it will retain the vertical speed at the moment of ground contact,
and measure the distance from touchdown until plane comes to stop.
When taking off, it shows the distance from start until liftoff.
If a flightplan is loaded, it will show bearing & distance to the next waypoint.
If an autopilot has been added to the plane (via systems.cfg), it can be utilized via
this gauge (by pressing "Z").
If a flightplan is loaded, it will follow the waypoints (retaining the current altitude).
If no flightplan is available, it will follow the current bearing.
Works in all planes that have either the mechanical hour counter or the AS92 radio (as it replaces that gauge).
