add virtual destructor

juci/source.h

@@ -60,6 +60,7 @@ namespace Source {
   class View : public Gtk::TextView {
   public:
     View();
+    virtual ~View() { }
     void ApplyConfig(const Config &config);
     void OnLineEdit(const std::vector<Range> &locations,
                     const Config &config);

juci/window.h

@@ -12,7 +12,7 @@ public:
   Window();
   MainConfig& main_config() { return main_config_; }
   Gtk::Box window_box_;
-
+  virtual ~Window() { }
 
   
 //private: