Unregister Composer's autoloader from the stack

Author: paulbalandan

system/Autoloader/Autoloader.php

@@ -312,6 +312,7 @@ protected function discoverComposerNamespaces()
         $paths    = $composer->getPrefixesPsr4();
         $classes  = $composer->getClassMap();
 
+        $composer->unregister();
         unset($composer);
 
         // Get rid of CodeIgniter so we don't have duplicates