change private to protected properties and method
check if error is defined

sometimes useful when reuse template
Bumped version to 0.4 dev
Replace deprecated code in process() method

Replace deprecated bind() method of Symfony\Component\Form\Form by submit() one
Revert "Replace deprecated code in process() method"

This reverts commit 22ed2a4a4357747d7a7fa59d22a15765bb225183.
added support for the use_forward config option