'EntityRepository' dependencies are accessible, using getters, after instantiation.

Good morning,

An `EntityRepository` object is created using an `EntityManager` and a Mapping `ClassMetadata` object but -previously - those dependencies were not publicly accessible.  I've been creating a `QueryBuilder` using `EntityRepository::createQueryBuilder()` to get a hold of the `EntityManager`, which is a little silly.  

I added a unit test for `EntityRepository` and made both dependencies accessible.

Thanks,
Dan
MUST stay `protected`