Integrate visibility Star widget into editing flow

This also removes some incorrect code from the clear() function for the
DiveInfo tab. Putting the readOnly() calls for the DiveNotes tab there was
wrong.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-ui/maintab.h

@@ -23,6 +23,7 @@ struct NotesBackup{
 	QString buddy;
 	QString suit;
 	int rating;
+	int visibility;
 	QString divemaster;
 };
 
@@ -54,6 +55,7 @@ public Q_SLOTS:
 	void on_suit_textChanged(const QString& text);
 	void on_notes_textChanged();
 	void on_rating_valueChanged(int value);
+	void on_visibility_valueChanged(int value);
 
 private:
 	Ui::MainTab *ui;