Robot: modernize C++11

* use nullptr

src/Mod/Robot/Gui/Workbench.cpp

@@ -92,28 +92,28 @@ void Workbench::activated()
     const char* RobotAndTrac[] = {
         "Robot_InsertWaypoint",
         "Robot_InsertWaypointPreselect",
-        0};
+        nullptr};
 
     const char* Robot[] = {
         "Robot_AddToolShape",
         "Robot_SetHomePos",
         "Robot_RestoreHomePos",
-        0};
+        nullptr};
 
     const char* Empty[] = {
         "Robot_InsertKukaIR500",
         "Robot_InsertKukaIR16",
         "Robot_InsertKukaIR210",
         "Robot_InsertKukaIR125",
-        0};
+        nullptr};
 
     const char* TracSingle[] = {
         "Robot_TrajectoryDressUp",
-        0};
+        nullptr};
 
     const char* TracMore[] = {
         "Robot_TrajectoryCompound",
-        0};
+        nullptr};
 
     std::vector<Gui::TaskView::TaskWatcher*> Watcher;