Fix InspectorGadget unserialization

library/ZendAfi/Controller/Plugin/InspectorGadget.php

@@ -120,7 +120,7 @@ class ZendAfi_Controller_Plugin_InspectorGadget extends Zend_Controller_Plugin_A
                               },
                               $this->_calls);
 
-    foreach($this->_calls as $call)
+    foreach(array_filter($this->_calls, 'is_object') as $call)
       $html .= '<li>' . $call->render() . '</li>';
 
     return $html . '</ol></div>';