Port tone equalizer from ART

Merge with local adjustments tone equalizer image processing function
for consistent results.

To-do: Enable for batch editing and add pivot/colormap to the local
adjustments version.

rtgui/thumbnail.cc

@@ -462,6 +462,7 @@ void Thumbnail::setProcParams (const ProcParams& pp, ParamsEdited* pe, int whoCh
         || pparams->epd != pp.epd
         || pparams->fattal != pp.fattal
         || pparams->sh != pp.sh
+        || pparams->toneEqualizer != pp.toneEqualizer
         || pparams->crop != pp.crop
         || pparams->coarse != pp.coarse
         || pparams->commonTrans != pp.commonTrans