Use categorized logging for QGestureManager.

Task-number: QTBUG-40461
Task-number: QTBUG-15768
Task-number: QTBUG-38925
Change-Id: I4b422b2b041a44ee8c24683ab2947cccfe422126
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>
Make the defaultSectionSize property of QHeaderView style dependent

Add new enum items PM_HeaderDefaultSectionSizeHorizontal and
PM_HeaderDefaultSectionSizeVertical to QStyle and get corresponding
values in QHeaderView. This way we get rid of some magic constants in
QHeaderView and we can have reasonable values for the default section
size for high-DPI displays.

[ChangeLog][QtWidgets][QHeaderView] Default section size is now style-dependent by default.

[ChangeLog][QtWidgets][QHeaderView] Added resetDefaultSectionSize().

Change-Id: I44e152c5cf0bec1e5d78e1e62f47a2d1f761dfbf
Reviewed-by: Thorbjørn Lund Martsum <tmartsum@gmail.com>