$FG_ROOT/Aircraft/f16/Hud/f16.xml and here as an example and for aircraft
to use so they don't have to refer to the f16 ... at least for now, until
the transition is completed)
was the style of the old HUD, and it should be fully-compatible ...)
- remove erroneous <modulo> from f16.xml. This isn't even read there.
- enable nadir and zenith (they are just too pretty to ignore them :-)
- various tweaks
$ fgfs --aircraft=f16-3d --prop:hud=Huds/f16.xml --prop:sim/hud/visibility\[1\]=1
The hud path is for now expected in /hud. This will, of course, be changed
later. The old and new HUD code don't match exactly when laid one over the
other yet, and the new HUD's tapes don't work.
