Add roles to the dataChanged slots in views.

Add roles to the dataChanged slots in views.

This is a source incompatible change.

This is for consistency with the signal for the lifetime of Qt5. I could
imagine people trying to override a virtual function (in a new class while
using the Qt5 library) with the arguments of
the signal and have that fail due to the arguments not being correct.

It also allows ignoring dataChange events when they are known not to be for roles
which are relevant to particular views or delegates.

Change-Id: Ica191835125c1c8fdaf665debb62d635e81700dc
Reviewed-by: David Faure <faure@kde.org>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>