Merge branch '2.3' into 2.7

* 2.3:
  [HttpFoundation] Fix transient test
  [HttpFoundation] Add a dependency on the mbstring polyfill
  add readme files where missing
  Don't use reflections when possible
  [Form] Update form tests after the ICU data update
  [Intl] Update tests and the number formatter to match behaviour of the intl extension
  [Intl] Update the ICU data to version 55
  [Intl] Fix the update-data.php script in preparation for ICU 5.5
  Use constant instead of function call.
  fixed test name
  automatically generate safe fallback filename

Conflicts:
	src/Symfony/Component/Debug/Debug.php
	src/Symfony/Component/HttpFoundation/composer.json
	src/Symfony/Component/Serializer/Tests/Normalizer/GetSetMethodNormalizerTest.php

Author: nicolas-grekas

Tests/Form/Type/EntityTypeTest.php

@@ -796,7 +796,7 @@ public function testChoicesForValuesOptimization()
 
         $this->persist(array($entity1, $entity2));
 
-        $field = $this->factory->createNamed('name', 'Symfony\Bridge\Doctrine\Form\Type\EntityType', null, array(
+        $field = $this->factory->createNamed('name', 'entity', null, array(
             'em' => 'default',
             'class' => self::SINGLE_IDENT_CLASS,
             'choice_label' => 'name',