Merge branch '2.6' into 2.7

* 2.6: (21 commits)
  bumped Symfony version to 2.6.8
  updated VERSION for 2.6.7
  updated CHANGELOG for 2.6.7
  bumped Symfony version to 2.3.29
  updated VERSION for 2.3.28
  update CONTRIBUTORS for 2.3.28
  updated CHANGELOG for 2.3.28
  [Debug] Fixed ClassNotFoundFatalErrorHandlerTest
  [SecurityBundle] use access decision constants in config
  [SecurityBundle] use session auth constants in config
  PhpDoc fix in AbstractRememberMeServices
  [Filesystem] Simplified an if statement
  [SecurityBundle] Use Enum Nodes Instead Of Scalar
  [Debug 2.3] Fix test for PHP7
  [HttpKernel] Check if "symfony/proxy-manager-bridge" package is installed
  [Translation] simplify getMessages.
  [Framework][Translation] added test for debug command.
  Run tests on hhvm instead of hhvm-nightly
  Use HTTPS in README and some other fixes
  add more entropy to generated classnames
  ...

Conflicts:
	.travis.yml
	src/Symfony/Component/HttpKernel/Kernel.php

Author: fabpot

Http/RememberMe/AbstractRememberMeServices.php

@@ -217,7 +217,7 @@ final public function loginSuccess(Request $request, Response $response, TokenIn
      * @param array   $cookieParts
      * @param Request $request
      *
-     * @return TokenInterface
+     * @return UserInterface
      */
     abstract protected function processAutoLoginCookie(array $cookieParts, Request $request);