fix(*): don't use instanceof to detect arrays

this breaks when multiple javascript contexts are involved - like in node-webkit

see original PR: #1966

Closes #1966

src/ng/filter/filter.js

@@ -106,7 +106,7 @@
  */
 function filterFilter() {
   return function(array, expression, comperator) {
-    if (!(array instanceof Array)) return array;
+    if (!isArray(array)) return array;
     var predicates = [];
     predicates.check = function(value) {
       for (var j = 0; j < predicates.length; j++) {

src/ng/filter/orderBy.js

@@ -89,7 +89,7 @@
 orderByFilter.$inject = ['$parse'];
 function orderByFilter($parse){
   return function(array, sortPredicate, reverseOrder) {
-    if (!(array instanceof Array)) return array;
+    if (!isArray(array)) return array;
     if (!sortPredicate) return array;
     sortPredicate = isArray(sortPredicate) ? sortPredicate: [sortPredicate];
     sortPredicate = map(sortPredicate, function(predicate){