FIX: can not save project when modify bed type in the scene

Change-Id: Iaea1bef142edcf0c68a64cfa1f3b1d309b96f251

src/slic3r/GUI/Plater.hpp

@@ -187,6 +187,7 @@ public:
 
     bool is_project_dirty() const;
     bool is_presets_dirty() const;
+    void set_plater_dirty(bool is_dirty);
     void update_project_dirty_from_presets();
     int  save_project_if_dirty(const wxString& reason);
     void reset_project_dirty_after_save();