Add dm input option to commands that requires it

[franmomu]

Feature Request

Q	A
New Feature	yes
RFC	no
BC Break	no

Summary

Right now it gets the documentManager from a helper:

mongodb-odm/lib/Doctrine/ODM/MongoDB/Tools/Console/Command/Schema/AbstractCommand.php

Lines 61 to 65 in 3171964

	/** @return DocumentManager */
	protected function getDocumentManager()
	{
	return $this->getHelper('documentManager')->getDocumentManager();
	}

we can add it as an input option and have something similar to AbstractEntityManagerCommand, that way we could use these commands directly from the bundle instead of creating proxy commands.