Turn almost all Listeners into abstract interfaces

rtgui/distortion.cc

@@ -84,14 +84,17 @@ void Distortion::setDefaults (const ProcParams* defParams, const ParamsEdited* p
     }
 }
 
-void Distortion::adjusterChanged (Adjuster* a, double newval)
+void Distortion::adjusterChanged(Adjuster* a, double newval)
 {
-
     if (listener) {
         listener->panelChanged (EvDISTAmount, Glib::ustring::format (std::setw(4), std::fixed, std::setprecision(3), a->getValue()));
     }
 }
 
+void Distortion::adjusterAutoToggled(Adjuster* a, bool newval)
+{
+}
+
 void Distortion::setBatchMode (bool batchMode)
 {