Bump version number to 5.4.1

Change-Id: I54231de422ffc63162e49c587f371c56c3312210
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
QColorDialog: Fix picking screen colors inside QColorPicker

If you click "Pick screen color" and move mouse over QColorPicker (the square with gradients)
unexpected things will happen: black will be picked half the times.

This is because QColorPicker's black cross is painted under our mouse cursor.

Although "pick screen color"'s use case is to pick colors in other windows, there's no reason
to not make it work on QColorDialog itself too.

Task-number: QTBUG-43288
Change-Id: I03ca02148cc15ad41d545723d4ac4f5a82842b4b
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>