Gui : susbtitute dot with local decimal separator for spin boxes

Main goal is to improve user-friendlyness for several locales
 Substitution of dot is performed :
 * Always if dot is neither decimal nor group/thousand separator of current locale
 * Only on NUMPAD dot if dot is not decimal but is group separator of current locale

src/Gui/Application.cpp

@@ -2080,6 +2080,12 @@ void Application::runApplication(void)
         WheelEventFilter* filter = new WheelEventFilter(&mainApp);
         mainApp.installEventFilter(filter);
     }
+    
+    //filter keyboard events to substitute decimal separator
+    if (hGrp->GetBool("SubstituteDecimalSeparator", false)) {
+        KeyboardFilter* filter = new KeyboardFilter(&mainApp);
+        mainApp.installEventFilter(filter);
+    }
 
 #if defined(HAVE_QT5_OPENGL)
     {