Gui: Use auto and range-based for (#7481)

* On lines where the variable type is obvious from inspection, avoid repeating the type using auto. 
* When possible use a ranged for loop instead of begin() and end() iterators

src/Gui/DlgActivateWindowImp.cpp

@@ -64,7 +64,7 @@ DlgActivateWindowImp::DlgActivateWindowImp(QWidget* parent, Qt::WindowFlags fl)
     QWidget* activeWnd = getMainWindow()->activeWindow();
 
     for (QList<QWidget*>::Iterator it = windows.begin(); it != windows.end(); ++it) {
-        QTreeWidgetItem* item = new QTreeWidgetItem(ui->treeWidget);
+        auto item = new QTreeWidgetItem(ui->treeWidget);
         QString title = (*it)->windowTitle();
         title.replace(QLatin1String("[*]"), QLatin1String(""));
         if ((*it)->isWindowModified())