Grid Examples: Do not focus menu buttons on page load (pull #354)

For issue #160, fix issue where menubutton elements in the grids were receiving focus when the page loaded. They should not be focused automatically.

examples/grid/js/menuButton.js

@@ -393,7 +393,7 @@ aria.widget.MenuButton.prototype.initMenuButton = function () {
     }
   }
 
-  this.closeMenu();
+  this.closeMenu(false, false);
 
   var self = this;