Menus: Improve performance for title live updating. Add `change` event for IE < 9.

props helen, SergeyBiryukov.
fixes #23076.
Built from https://develop.svn.wordpress.org/trunk@29672


git-svn-id: http://core.svn.wordpress.org/trunk@29446 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/nav-menu.js

@@ -534,7 +534,7 @@ var wpNavMenu;
 
 		initPreviewing : function() {
 			// Update the item handle title when the navigation label is changed.
-			$( 'body' ).on( 'input', '.edit-menu-item-title', function(e) {
+			$( '#menu-to-edit' ).on( 'change input', '.edit-menu-item-title', function(e) {
 				var input = $( e.currentTarget ), title, titleEl;
 				title = input.val();
 				titleEl = input.closest( '.menu-item' ).find( '.menu-item-title' );