Adding ADD/SET mechanism to Fattal HDR tool + PartialPaste dialog gui

+ range of Beta limited to 0.7 <> 1.3.

ADD/SET mechanism was missing for EPD tool too, so it's included in this
commit.

see #4168

rtgui/fattaltonemap.h

@@ -40,5 +40,7 @@ public:
 
     void adjusterChanged (Adjuster* a, double newval);
     void enabledChanged  ();
+    void setAdjusterBehavior (bool alphaAdd, bool betaAdd);
+
 };