remove utf8_cast functions

include/nana/gui/widgets/checkbox.hpp

@@ -56,14 +56,8 @@ namespace drawerbase
 			void mouse_up(graph_reference, const arg_mouse&)	override;
 		public:
 			implement * impl() const;
-		private:
-			void _m_draw_background(graph_reference);
-			void _m_draw_checkbox(graph_reference, unsigned first_line_height);
-			void _m_draw_title(graph_reference);
 		private:
 			static const int interval = 4;
-			widget* widget_;
-			std::unique_ptr<implement> imptr_;
 			implement * impl_;
 		};
 	}//end namespace checkbox