Add access to documentation and to online html page via Help menu * main-window.cc, main-window.h (main_window::open_online_documentation_page): Add for calling online documentation page at GNU website. (main_window::construct): Add "Documentation" item to Help menu with submenu consisting of "On Disk" and "Online". Switch around order of "Agora" and "Octave Forge". Connect open_online_documentation_page to menu "Online" trigger and focus_documentation to menu "On Disk" trigger.

--- a/libgui/src/main-window.h
+++ b/libgui/src/main-window.h
@@ -86,9 +86,10 @@
   void new_file ();
   void open_file ();
   void open_file (const QString& file_name);
+  void open_online_documentation_page ();
   void open_bug_tracker_page ();
+  void open_octave_forge_page ();
   void open_agora_page ();
-  void open_octave_forge_page ();
   void process_settings_dialog_request ();
   void show_about_octave ();
   void notice_settings ();