This fixes the problem on GTK where the text was unreadable when
using a "dark" theme.
And fixes the double display of the real tooltip and the tip panel
being displayed at the same time on GTK and OSX. It seems that
the "disabling/reenabling" of tooltips doesn't take affect right
away anymore...maybe it never did.
This relies on three new nyquist scripts to actually do the editing. The peak-snapping code in FrequencyWindow has been extracted into a new class, SpectrumAnalyst, to provide peak-snapping in spectrogram too.
final but it's a big improvement. Reversed a couple changes from
original indication scheme that are no longer necessary. Unfortunately
it's really hard to remove colors from AllThemeResources.h.