Move FormErrorHandler to the bundle

[hpatoio]

I think that FormErrorHandler should be moved from jms/serializer to jms/serializer-bundle because it handle Symfony forms and not a generic type.

I can submit PRs to both repo but I first would like to know if I'm right or I'm missing something.

[goetas]

the tricky part it that somebody can be using the symfony form component without the symfony framework itself. for that reason this class has to stay here (or in a separate package... but this only for 2.0)