[ticket/13032] Update Symfony Components to 2.3.19

PHPBB3-13032
[ticket/13032] Also update symfony/css-selector and pin it down.

PHPBB3-13032
Merge pull request #2917 from bantu/ticket/13032

[ticket/13032] Update Symfony Components to 2.3.19
Merge branch 'develop-ascraeus' into develop