Fix return value for QList/QSet properties

Add initialization of QObject properties from XMI-declared default values

Change-Id: I1a5c097463aa492b121991cf6e569b38222cfdda
Reviewed-by: Sandro S. Andrade <sandroandrade@kde.org>
Updating examples and tests

Disabling plugins building by now

Change-Id: Idcdcca005520d585d74c579e6fa42dc76d42be8e
Reviewed-by: Sandro S. Andrade <sandroandrade@kde.org>