Added Symfony 2.4/FrameworkExtraBundle 3.x notice on ParamConverter
Merge pull request #272 from kix/1.4

Added Symfony 2.4/FrameworkExtraBundle 3.x notice on ParamConverter
Fix possible `PDO Unknown database` error
This patches a possible `Unable to open PDO connection [wrapped: SQLSTATE[42000] [1049] Unknown database '<db_name>']` when the dsn is not ending with a `;`.
Related to #159