Symfony 3.0 Support

Merge pull request #3 from yann-eugone/symfony-3-compatibility

Symfony 3 compatibility

v1.3

Removed Symfony 3.0 build because of Form refactoring

v1.2

Added Twig extension that add ability to render enum value label

v1.1

Fixed class name typo in Bundle DI extension

v1.0

Re-enable Symfony 3.0 in Travis tests, but remove php 5.4