Checking instanceof Arrays cross frames. fix #1195

Using the instanceof Array method will not work for arrays created on another frame,
Instead of instanceof we should use Array.isArray, but this is not supported on IE8.
So vjs.obj.isArray shim was created for the isArray method.

src/js/component.js

@@ -471,7 +471,7 @@ vjs.Component.prototype.initChildren = function(){
 
   if (children) {
     // Allow for an array of children details to passed in the options
-    if (children instanceof Array) {
+    if (vjs.obj.isArray(children)) {
       for (var i = 0; i < children.length; i++) {
         child = children[i];