Indicate that there are unsaved changes with a '*' in the window title

This seems to be a fairly common way to indicate this property.

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

qthelper.cpp

@@ -34,6 +34,7 @@
 #include <QtConcurrent>
 #include "divepicturewidget.h"
 #include "subsurfacewebservices.h"
+#include "mainwindow.h"
 
 #include <libxslt/documents.h>
 
@@ -1057,3 +1058,8 @@ extern "C" bool canReachCloudServer()
 {
 	return CheckCloudConnection::checkServer();
 }
+
+extern "C" void updateWindowTitle()
+{
+	MainWindow::instance()->setTitle();
+}