[FrameworkBundle] fix browserkit requirement
Merge branch '2.5' into 2.6

* 2.5:
  [FrameworkBundle] fix browserkit requirement
  [TwigBridge] fix form requirement
  [FrameworkBundle] fix http-foundation requirement
  [CssSelector] added the license of the Python library we ported to PHP
  [SecurityBundle] avoid unneeded work

Conflicts:
	src/Symfony/Bridge/Twig/composer.json
	src/Symfony/Bundle/FrameworkBundle/composer.json
	src/Symfony/Component/HttpKernel/composer.json