Implement both getName and getBlockPrefix for symfony 2.8 based projects (#189)

keep getName implemented while we still support symfony 2.8

As explained in symfony upgrade document: https://github.com/symfony/symfony/blob/2.8/UPGRADE-2.8.md

Author: jmeyo

Form/Extension/Type/LocaleType.php

@@ -54,6 +54,15 @@ public function getParent()
         return 'Symfony\\Component\\Form\\Extension\\Core\\Type\\ChoiceType';
     }
 
+    /**
+     * @deprecated implement getBlockPrefix in place of getName, implement both for symfony 2.8 based projects
+     * {@inheritdoc}
+     */
+    public function getName()
+    {
+        return $this->getBlockPrefix();
+    }
+    
     /**
      * {@inheritdoc}
      */