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
Instruments/*.xml ... single components, like the gload display
Sets/*.xml ... combinations of components
There's no difference in filetypes between "sets" and "instruments". It's
just easier to find things that way. Note that new and old files are never
mixed in one dir.