[gtkmm-documentation] Improve the UI definitions in the menu examples

[Kjell Ahlstedt <kjellahl src gnome org>]

commit f62d10abe1bfb7dbbef0c041ada4b6e1e542a3fe
Author: Kjell Ahlstedt <kjell ahlstedt bredband net>
Date:   Thu Nov 27 09:03:20 2014 +0100

    Improve the UI definitions in the menu examples
    
    * examples/book/menus/main_menu/examplewindow.cc: Change to "requires gtk+ 3.4".
    * examples/book/menus_and_toolbars/examplewindow.cc: Add "requires gtk+ 3.4".

 examples/book/menus/main_menu/examplewindow.cc    |    3 +--
 examples/book/menus_and_toolbars/examplewindow.cc |    1 +
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/examples/book/menus/main_menu/examplewindow.cc b/examples/book/menus/main_menu/examplewindow.cc
index 1f365c8..c3de545 100644
--- a/examples/book/menus/main_menu/examplewindow.cc
+++ b/examples/book/menus/main_menu/examplewindow.cc
@@ -58,10 +58,9 @@ ExampleWindow::ExampleWindow()
   m_refBuilder = Gtk::Builder::create();
 
   Glib::ustring ui_info =
-    "<?xml version='1.0' encoding='UTF-8'?>"
     "<!-- Generated with glade 3.18.3 -->"
     "<interface>"
-    "  <requires lib='gtk+' version='3.12'/>"
+    "  <requires lib='gtk+' version='3.4'/>"
     "  <object class='GtkToolbar' id='toolbar'>"
     "    <property name='visible'>True</property>"
     "    <property name='can_focus'>False</property>"
diff --git a/examples/book/menus_and_toolbars/examplewindow.cc 
b/examples/book/menus_and_toolbars/examplewindow.cc
index 32c9710..010c497 100644
--- a/examples/book/menus_and_toolbars/examplewindow.cc
+++ b/examples/book/menus_and_toolbars/examplewindow.cc
@@ -107,6 +107,7 @@ ExampleWindow::ExampleWindow(const Glib::RefPtr<Gtk::Application>& app)
     "  </menu>"
     ""
     "<!-- Generated with glade 3.18.3 -->"
+    "  <requires lib='gtk+' version='3.4'/>"
     "  <object class='GtkImage' id='image_rain'>"
     "    <property name='visible'>True</property>"
     "    <property name='can_focus'>False</property>"