Adapt to the change from gaudi/Gaudi!1766

In gaudi/Gaudi!1766 (merged), the refactoring of SmartIF to support concrete types (or better, types not implementing queryInterface), requires the introduction of a new method to IInterface, which has to be implemented by all classes inheriting from IInterface. This method is implicitly implemented when inheriting from implements<...>, but it has to be explicitly implemented when inheriting directly from IInterface.

gaudi/Gaudi!1766 (merged) also changes the signature of another method in IInterface that require adaptation.

This MR adds the missing implementations.