Made this bundle compatible to all Symfony 2.2 versions

Currently this bundle is installable for Symfony 2.0 only. In order to install it with the latest Symfony 2.2 version the requirements have to be modified. Please don't ask why I am doing a PR for a Symfony 2.2 version :)
Merge pull request #1 from frastel/patch-1

Made this bundle compatible to all Symfony 2.2 versions