[Part] allow to edit helices via a dialog

+ add class ViewProviderPrimitive to avoid to re-implement setEdit/unsetEdit methods for each sub-class separately
+ avoid using global variables
+ when editing a feature directly pass it to the dialogs
+ when editing a feature then do not use active document as this could point to the wrong object
+ fix undo/redo message
+ re-add '3D View' button to location dialog

src/Mod/Part/Gui/AppPartGui.cpp

@@ -157,6 +157,7 @@ PyMOD_INIT_FUNC(PartGui)
     PartGui::ViewProviderAttachExtensionPython      ::init();
     PartGui::ViewProviderPartExt                    ::init();
     PartGui::ViewProviderPart                       ::init();
+    PartGui::ViewProviderPrimitive                  ::init();
     PartGui::ViewProviderEllipsoid                  ::init();
     PartGui::ViewProviderPython                     ::init();
     PartGui::ViewProviderBox                        ::init();