It was supposed to be in ft/min, but everything except AIAircraft was
using it as ft/sec. Change the name to AIBase::vs_fps and ensure the
same unit is used everywhere.
Disable GPS::finalLegCourseTest, and one of the View index tests,
so that tests pass successfully.
Also add some default properties so the skeleton traffic tests start
up without crashing.
Capture the current behaviour of Increment/DecrementWaypoint in
AI flightplans, prior to making some simplifications. Especially try
to test the behaviour of the ‘increment and erase’ logic.