[Security] removed deprecated classes
[Translation] removed deprecated classes
removed deprecated stuff in the fragment sub-framework
removed deprected way to declared trusted proxies
[HttpFoundation] removed deprecated Request::splitHttpAcceptHeader() method
[Yaml] removed deprecated support of PHP parsin when parsing YAML files
[HttpFoundation] removed deprecated session methods
[Validator] removed deprecated constraints
[Validator] removed deprecated methods
[Form] removed deprecated methods and classes
[FrameworkBundle] removed deprecated cookie options
[FrameworkBundle] removed deprecated options
[TwigBundle] removed deprecated syntax