Test components using their lowest possible deps
Merge remote-tracking branch 'symfony/2.3' into lowest-25

* symfony/2.3:
  Test components using their lowest possible deps

Conflicts:
	src/Symfony/Bridge/Doctrine/composer.json
	src/Symfony/Bridge/Twig/composer.json
	src/Symfony/Bundle/FrameworkBundle/composer.json
	src/Symfony/Bundle/SecurityBundle/composer.json
	src/Symfony/Bundle/TwigBundle/composer.json
	src/Symfony/Component/DependencyInjection/composer.json
	src/Symfony/Component/EventDispatcher/composer.json
	src/Symfony/Component/Form/composer.json
	src/Symfony/Component/HttpKernel/composer.json
	src/Symfony/Component/Routing/composer.json
	src/Symfony/Component/Security/composer.json
	src/Symfony/Component/Validator/composer.json
Test lowest versions of dependencies