doctrine/doctrine2 — pull request #960 by drealecs (2014-02-23 18:13:40+00:00)
Title: allow passing EntityManagerInterface when creating a HelperSet

I've been "extended" EntityManager by decoration-wrapping and was trying to pass my EntityManager to ```ConsoleRunner::createHelperSet()``` and the type-hinting didn't allow it.
This fix will allow the ```$entityManager``` parameter to be an instance of ```EntityManagerInterface``` instead of ```EntityManager```