remove on_pen_cmd_result for it isn't used at present

@@ -715,10 +715,6 @@
 			window.Native.pen_cmd(cmd);
 		}
 
-		function on_pen_cmd_result(cmd,result){
-
-		}
-
 		function on_pen_point(x, y, nPress) {
 
 				if (rotate_degree == 0) {