fix index calculation to skip templates

Sortable.js

@@ -949,9 +949,11 @@
 	 */
 	function _index(/**HTMLElement*/el) {
 		var index = 0;
-		while (el && (el = el.previousElementSibling) && (el.nodeName.toUpperCase() !== 'TEMPLATE')) {
+		while (el && (el = el.previousElementSibling)) {
+			if (el.nodeName.toUpperCase() !== 'TEMPLATE') {
 				index++;
 			}
+		}
 		return index;
 	}