Suggestions for QAbstractItemView

QAbstractItemView::setModel() is virtual, what is fine, while QAbstractItemView::setItemDelegate() isn't, what makes it hacky to connect to
the current delegate sizeHintChanged() signal.

Also QListView::setGridSize what forces the user to clean internally some things in the cache isn't virtual.

QAbstractItemView should be virtual (the virtual table nowadays is not that expensive), since one can't never expect what the class that is inheriting QAbstractItemView will do.