added shortcut for closing the window

pd/nw/pd_canvas.html

@@ -516,7 +516,9 @@ function nw_create_patch_window_menus (name) {
         tooltip: l('menu.close_tt'),
         click: function() {
             pdgui.menu_close(name);
-        }
+        },
+        key: 'w',
+        modifiers: "ctrl"
     }));
 
     // Quit Pd