filter: when a filter preset is selected, suggest its name on save

The goal here is to let the user edit already existing sets and
save them using their old name. This is a stop-gap measure until
we get a proper filter-set editing interface.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

desktop-widgets/simplewidgets.h

@@ -142,7 +142,7 @@ private:
 class AddFilterPresetDialog : public QDialog {
 	Q_OBJECT
 public:
-	explicit AddFilterPresetDialog(QWidget *parent);
+	explicit AddFilterPresetDialog(const QString &defaultName, QWidget *parent);
 	QString doit(); // returns name of filter preset or empty string if user cancelled the dialog
 private
 slots: