QTreeWidget::setItemWidget should allow to control the alignment of widget

QTreeWidget::setItemWidget() should allow to control the alignment of the added widget.

Change:

void setItemWidget(QTreeWidgetItem *item, int column, QWidget *widget);
(see http://doc.qt.nokia.com/4.8-snapshot/qtreewidget.html#setItemWidget)

To:

void setItemWidget(QTreeWidgetItem *item, int column, QWidget *widget, Qt::Alignment alignment = Qt:: AlignLeft);

That way function would be backward compatible but give user the ability, if widget is smaller than the cell, to center it or to right align it in the cell.