Sketcher New Feature: Toggle Mode for Reference/Driving constraints

===================================================================

It allows to create constraints directly into Reference or Driving mode.

It does not include icons

src/Mod/Sketcher/Gui/Workbench.cpp

@@ -204,7 +204,9 @@ inline void SketcherAddWorkbenchConstraints<Gui::MenuItem>(Gui::MenuItem& cons){
             << "Sketcher_ConstrainRadius"
             << "Sketcher_ConstrainAngle"
             << "Sketcher_ConstrainSnellsLaw"
-            << "Sketcher_ConstrainInternalAlignment";
+            << "Sketcher_ConstrainInternalAlignment"
+            << "Separator"
+            << "Sketcher_ConstraintCreationMode";
 }
 
 template <>
@@ -225,7 +227,9 @@ inline void SketcherAddWorkbenchConstraints<Gui::ToolBarItem>(Gui::ToolBarItem&
             << "Sketcher_ConstrainDistance"
             << "Sketcher_ConstrainRadius"
             << "Sketcher_ConstrainAngle"
-            << "Sketcher_ConstrainSnellsLaw";
+            << "Sketcher_ConstrainSnellsLaw"
+            << "Separator"
+            << "Sketcher_ConstraintCreationMode";            
 }
 
 template <typename T>