Merge remote branch 'lsmith77/serializer'

* lsmith77/serializer:
  make it possible to read the normalizerCache when inheriting

src/Symfony/Component/Serializer/Serializer.php

@@ -30,7 +30,7 @@ class Serializer implements SerializerInterface
 {
     private $normalizers = array();
     private $encoders = array();
-    private $normalizerCache = array();
+    protected $normalizerCache = array();
 
     /**
      * @param mixed $value value to test