TODO logger.error -> logger.debug - LATER.
special handling for common use case of completely empty *.efactory;
just to avoid the confusing Exception & log.
FIX avoid NPE for invalid import (still needs a Validation, ideally)
FIXED added support for 'forgotten' (?) handling of Integer
(EIntegerObject), as opposed to primitive int, etc. Incl. new oneInteger
on TestModel.ecore plus src-emf/ new gen. code (with a lot of whitespace
and doc changes and similar, due to gen. by newer EMF version).
PS: Still NOK e.g. for BigDecimal.. grammar needs to be changed.