Created GetRowByItem() to fix the Scrolling of the Object List to selected item under all platforms

+ temporary suppressed object/part mane editing under OSX

src/slic3r/GUI/GUI_ObjectList.hpp

@@ -108,6 +108,8 @@ class ObjectList : public wxDataViewCtrl
     bool        m_parts_changed = false;
     bool        m_part_settings_changed = false;
 
+    int         m_selected_row = 0;
+
 public:
     ObjectList(wxWindow* parent);
     ~ObjectList();