changed Swiftmailer autoloader to use the Swiftmailer one (it automatically loads the init file)

src/Silex/Extension/SwiftmailerExtension.php

@@ -73,7 +73,9 @@ class SwiftmailerExtension implements ExtensionInterface
         });
 
         if (isset($app['swiftmailer.class_path'])) {
-            $app['autoloader']->registerPrefix('Swift_', $app['swiftmailer.class_path']);
+            require_once $app['swiftmailer.class_path'].'/Swift.php';
+
+            Swift::registerAutoload($app['swiftmailer.class_path'].'/swift_init.php');
         }
     }
 }