Patch from issue 1359: "Munsell correction - Lab adjustements" credits: jdesmis

Bundled new features besid the Lab tool enhancement (by jdesmis) :
   - curve to control skin tones in vibrance tool, credits: jdesmis
   - right click over SHCSelector (below the parametric curve) to reset to default values, credits: Hombre
   - colored bars around curves, credits: Hombre

rtgui/diagonalcurveeditorsubgroup.h

@@ -66,6 +66,7 @@ public:
 	virtual void updateBackgroundHistogram (CurveEditor* ce);
 	virtual void setColorProvider (ColorProvider* p);
 
+
 protected:
 	void storeCurveValues (CurveEditor* ce, const std::vector<double>& p);
 	void storeDisplayedCurve ();
@@ -82,6 +83,8 @@ protected:
 	void adjusterChanged (Adjuster* a, double newval);
 	bool adjusterEntered (GdkEventCrossing* ev, int ac);
 	bool adjusterLeft (GdkEventCrossing* ev, int ac);
+	void setSubGroupRangeLabels(Glib::ustring r1, Glib::ustring r2, Glib::ustring r3, Glib::ustring r4);
+	void setSubGroupBottomBarBgGradient();
 };
 
 #endif