Cleanup GraphicsView examples with the help of clang-tidy
- modernize-use-nullptr
- modernize-use-default-member-init
- modernize-use-override.IgnoreDestructors
- Some QList -> QVector changes
- use nullptr
- use normalized includes, remove unused includes
- fix style
Change-Id: I79347e55bfde52f6ae7749cc7093fbd442044020
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
6f4bc3942d