Merge branch '2.6' into 2.7

* 2.6:
  [2.6] Towards 100% HHVM compat
  [Security/Http] Fix test
  [Stopwatch] Fix test
  Minor fixes
  Towards 100% HHVM compat
  unify default AccessDeniedExeption message
  trigger event with right user (add test)
  [Security] Initialize SwitchUserEvent::targetUser on attemptExitUser
  [Form] Fixed: Data mappers always receive forms indexed by their names

Conflicts:
	src/Symfony/Bundle/FrameworkBundle/Controller/Controller.php
	src/Symfony/Component/VarDumper/Tests/CliDumperTest.php
	src/Symfony/Component/VarDumper/Tests/HtmlDumperTest.php

Author: nicolas-grekas

Exception/AccessDeniedException.php

@@ -18,7 +18,7 @@
  */
 class AccessDeniedException extends \RuntimeException
 {
-    public function __construct($message = 'Access Denied', \Exception $previous = null)
+    public function __construct($message = 'Access Denied.', \Exception $previous = null)
     {
         parent::__construct($message, 403, $previous);
     }