Added support framework.validation.transaltion_domain parameter

Hello!
In symfony more that v2.3 errors violation added with already pluralization:
src v2.3: https://github.com/symfony/symfony/blob/2.3/src/Symfony/Component/Validator/ExecutionContext.php#L92
src v2.5: https://github.com/symfony/symfony/blob/2.5/src/Symfony/Component/Validator/ExecutionContext.php#L95
src master: 
This pull request remove hardcoded 'validators' translation domain, to support    framework.validation.transaltion_domain parameter of app/config/config.yml