[BUGFIX] ReflectionService works for non-Entity inheritance members
As soon as a class which is not an entity was present as an
ancestor of an Entity (with at least one Entity descendant in
between), there was an Undefined Index error because the
ReflectionService proceeded on the assumption that everything
was an Entity, hence present in the ->classSchemata array.
This adds an additional check for the actual presence of
such an array index and proofs this behavior with a
Functional Test Fixture.
Releases: master, 2.0