Fix typos of QWheelEvent example

Just fixed typos with event and numPixels.

Change-Id: I8191d7e812ae9d3975a142d198d709d4f9f85b7f
Reviewed-by: hjk <hjk121@nokiamail.com>
QCommandLineOption: declare as shared

QCommandLineOptions are held in a QList in QCommandLineParser,
so they better be declared movable, which is one of the things
Q_DECLARE_SHARED enables.

Change-Id: I75c8185534b4e9c1ea4417a9507095c8a6512aab
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>