saving properties window state when changed

to not lose it on an unclean exit


## select and sort signal

sortIndicatorChanged is enough to detect selected and sorted column. sectionClicked isnt needed

i tested the sortIndicatorChanged signal by printing the signal name at the top of TransferListWidget::saveSettings()

	QMessageBox::information(0, tr(""), QObject::sender()->metaObject()->method(senderSignalIndex()).signature());

the result is that its sent both when a selected and non-selected column is clicked

* signals from clicking a selected column: sortIndicatorChanged then sectionClicked
* signals from clicking a non-selected column: sortIndicatorChanged then sectionClicked


## signal to multiple slots

the setCurrentIndex and setVisibility state will always be saved after the state is changed bc the slots are called in the order theyre connected

>http://stackoverflow.com/questions/1246933/order-of-slots-called-on-qobject

>If several slots are connected to one signal, the slots will be executed one after the other, in the order they have been connected, when the signal is emitted