[TwigBundle] removed deprecated syntax
merged branch fabpot/deprecated (PR #7227)

This PR was merged into the master branch.

Discussion
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[WIP] Removed deprecated stuff

Commits
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f2a8908 removed deprecated functionality from RouteCollection
4f4a5d1 [TwigBundle] removed deprecated syntax
45bd413 [FrameworkBundle] removed deprecated options
0bb5d01 [FrameworkBundle] removed deprecated cookie options
b3081e8 [Form] removed deprecated methods and classes
e0385a2 [Validator] removed deprecated methods
65e3b16 [Validator] removed deprecated constraints
4a70ddf [HttpFoundation] removed deprecated session methods
4e7943f [Yaml] removed deprecated support of PHP parsin when parsing YAML files
09a5969 [HttpFoundation] removed deprecated Request::splitHttpAcceptHeader() method
c28f1b0 removed deprected way to declared trusted proxies
5ff6006 removed deprecated stuff in the fragment sub-framework
0a06a7c [Translation] removed deprecated classes
67f6397 [Security] removed deprecated classes