[Intl] Updated stubs to reflect ICU 51.2
Merge branch '2.3'

* 2.3:
  added missing support for the new output API in PHP 5.4+
  Fixed bug introduced in #8675
  made the filesystem loader compatible with Twig 2.0
  bumped Symfony version to 2.3.4-DEV
  updated VERSION for 2.3.3
  updated CHANGELOG for 2.3.3
  bumped Symfony version to 2.2.6
  updated VERSION for 2.2.5
  update CONTRIBUTORS for 2.2.5
  updated CHANGELOG for 2.2.5
  [Intl] Updated stubs to reflect ICU 51.2
  replaced deprecated Twig features

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