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

DataCollector/ConfigDataCollector.php

@@ -75,7 +75,7 @@ public function collect(Request $request, Response $response, \Exception $except
             'wincache_enabled' => extension_loaded('wincache') && ini_get('wincache.ocenabled'),
             'zend_opcache_enabled' => extension_loaded('Zend OPcache') && ini_get('opcache.enable'),
             'bundles' => array(),
-            'sapi_name' => php_sapi_name(),
+            'sapi_name' => PHP_SAPI,
         );
 
         if (isset($this->kernel)) {