Don't read "/Spectrum/" preferences anywhere but in SpectrumPrefs.cpp.
Don't store global values in TrackArtist.
Possibly some day, there will be other instances of SpectrogramSettings so we
can have independent per-track settings.
This brings the builtin, LV2, and VAMP effects inline with the
Audio Units, LADSPA, and VST effects. All effects now share
a common UI.
This gives all effects (though not implemented for all):
User and factory preset capability
Preset import/export capability
Shared or private configuration options
Builtin effects can now be migrated to RTP, depending on algorithm.
LV2 effects now support graphical interfaces if the plugin supplies one.
Nyquist prompt enhanced to provide some features of the Nyquist Workbench.
It may not look like it, but this was a LOT of work, so trust me, there
WILL be problems and everything effect related should be suspect. Keep
a sharp eye (or two) open.
