title: Selected row in QTreeView / QStandardItemModel
body: <p>I am trying to implement an account structure (with subaccounts) in PyQt4, using a QTreeView and a QStandardItemModel. After a lot of trials and errors I have finally the tree view ready. Now, I want something to happen when I click a specific row in the tree view. My experience from the GTK toolkit suggests I would listen to some sort of signal emitted when a row is clicked and then write a signal handler to find out which row was clicked. I can't figure out how to do this in PyQt. Any suggestions?</p>