Added SimplificationDialog

src/slic3r/GUI/GUI_ObjectList.hpp

@@ -353,6 +353,7 @@ public:
     void split_instances();
     void rename_item();
     void fix_through_netfabb();
+    void simplify();
     void update_item_error_icon(const int obj_idx, int vol_idx) const ;
 
     void copy_layers_to_clipboard();