Changed signals and slots to new syntax, used nullptr and replaced
foreach with new C++11 range based for loops.
Also fixed a few minor flaws.
Task-number: QTBUG-60633
Change-Id: Ice4030133971912f96752d9d84c638c70fd73e35
Reviewed-by: Jesus Fernandez <Jesus.Fernandez@qt.io>
Reviewed-by: André Hartmann <aha_1980@gmx.de>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
3d67793a9e