A bug in weather-utility.nas caused constant computation
of wave parameters due to the fact that the wind speed
was ignored.
That code was ugly anyway, so it has been replaced by
property rules which don't create work for the nasal
garbage collector.
All required properties for the wave shader are now in
interpolator.xml, the snow-line computation lives in
metarinterpolator.xml
Read actual turbulence value from "turbulence-magnitude-norm" property,
not from its "...-override" switch (which is true when enabled, so
turbulence was always forced to "1.0").
make options
--wind=nnn@mm
--visibility
--visibility-miles
--ceiling
--turbulence
work again. These options now write properties in the
/environment/config/presets
branch. The values will be applied in the property-rules
in FGDATA/Environment/interpolator.xml
Corresponds to commit e86cecf4704a4bdcf43114245d8ac94adb1f1eef
in fg/next
