Add getChildrenWithType(EObject, Class<T>, Collection<Class<?extends T>)

* For the given EObject, this specialization returns the most nested
  ancestors of given type that does not have any ancestors of any
  of the provided admissible specializations.

Issue-Ref: 4104
Issue-Url: af3#4104



Signed-off-by: Simon Barner <barner@fortiss.org>