[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/ViewProvider.cpp

@@ -24,16 +24,22 @@
 #include "PreCompiled.h"
 
 #ifndef _PreComp_
+# include <QAction>
+# include <QMenu>
 #endif
 
 #include <Base/Console.h>
 #include <Base/Exception.h>
 #include <App/Document.h>
+#include <Gui/Application.h>
 #include <Gui/Command.h>
+#include <Gui/Control.h>
 
 #include <Mod/Part/App/PartFeature.h>
+#include <Mod/Part/App/PrimitiveFeature.h>
 
 #include "ViewProvider.h"
+#include "DlgPrimitives.h"
 
 
 using namespace PartGui;
@@ -94,6 +100,53 @@ void ViewProviderPart::applyTransparency(const float& transparency,
 
 // ----------------------------------------------------------------------------
 
+PROPERTY_SOURCE(PartGui::ViewProviderPrimitive, PartGui::ViewProviderPart)
+
+ViewProviderPrimitive::ViewProviderPrimitive()
+{
+}
+
+ViewProviderPrimitive::~ViewProviderPrimitive()
+{
+
+}
+
+void ViewProviderPrimitive::setupContextMenu(QMenu* menu, QObject* receiver, const char* member)
+{
+    QAction* act;
+    act = menu->addAction(QObject::tr("Edit %1").arg(QString::fromUtf8(getObject()->Label.getValue())), receiver, member);
+    act->setData(QVariant((int)ViewProvider::Default));
+    ViewProviderPart::setupContextMenu(menu, receiver, member);
+}
+
+bool ViewProviderPrimitive::setEdit(int ModNum)
+{
+    if (ModNum == ViewProvider::Default) {
+        if (Gui::Control().activeDialog())
+            return false;
+        PartGui::TaskPrimitivesEdit* dlg
+            = new PartGui::TaskPrimitivesEdit(dynamic_cast<Part::Primitive*>(getObject()));
+        Gui::Control().showDialog(dlg);
+        return true;
+    }
+    else {
+        ViewProviderPart::setEdit(ModNum);
+        return true;
+    }
+}
+
+void ViewProviderPrimitive::unsetEdit(int ModNum)
+{
+    if (ModNum == ViewProvider::Default) {
+        Gui::Control().closeDialog();
+    }
+    else {
+        ViewProviderPart::unsetEdit(ModNum);
+    }
+}
+
+// ----------------------------------------------------------------------------
+
 void ViewProviderShapeBuilder::buildNodes(const App::Property* , std::vector<SoNode*>& ) const
 {
 }