Cleanup some minor issues in the chart example:
- remove unused members
- use initializer list for members
- pass a proper role to dataChanged()
- honor roles parameter in PieView::dataChanged()
- use nullptr instead 0
- use new-style connect
- fix indentation and other whitespaces
Change-Id: Idb212b07c006fe3ae31bee9cd9b1ba4d03043b5e
Reviewed-by: André Hartmann <aha_1980@gmx.de>
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
8c685b765b