pass QString by const reference instead of value * files-dockwidget.cc, files-dockwidget.h, history-dockwidget.h, file-editor-interface.h, file-editor-tab.cc, file-editor-tab.h, file-editor.cc, file-editor.h, main-window.cc, main-window.h, octave-qt-event-listener.h, parser.cc, parser.h, webinfo.cc, webinfo.h, resource-manager.cc, resource-manager.h: For all functions that take QString arguments, use "const Qstring&" instead of passing QString by value.

--- a/libgui/src/octave-qt-event-listener.h
+++ b/libgui/src/octave-qt-event-listener.h
@@ -41,7 +41,7 @@
     void quit_debug_mode ();
 
   signals:
-    void current_directory_has_changed_signal (QString directory);
+    void current_directory_has_changed_signal (const QString& directory);
     void entered_debug_mode_signal ();
     void quit_debug_mode_signal ();
 };