[gtkmm] Widget: Add remove_action_group().

[Murray Cumming <murrayc src gnome org>]

commit fa707a807c2cc788061df46d1128c21da3c58340
Author: Murray Cumming <murrayc murrayc com>
Date:   Tue Sep 17 13:22:12 2013 +0200

    Widget: Add remove_action_group().
    
    * gtk/src/widget.[hg|ccg]: Now that we know that
      gtk_widget_insert_action_group() can take NULL to mean this.
      See GTK+ bug #708150 .

 gtk/src/widget.ccg |    6 +++++-
 gtk/src/widget.hg  |    9 +++++++++
 2 files changed, 14 insertions(+), 1 deletions(-)
---
diff --git a/gtk/src/widget.ccg b/gtk/src/widget.ccg
index 0a39e9e..ba53ce8 100644
--- a/gtk/src/widget.ccg
+++ b/gtk/src/widget.ccg
@@ -721,10 +721,14 @@ void Widget::unset_cursor()
   gtk_widget_override_cursor(gobj(), 0, 0);
 }
 
-
 void Widget::transform_cairo_context_to_window(const Cairo::RefPtr<Cairo::Context>& cr, const 
Glib::RefPtr<const Gdk::Window>& window)
 {
   gtk_cairo_transform_to_window((cr)->cobj(), gobj(), 
const_cast<GdkWindow*>(Glib::unwrap<Gdk::Window>(window)));
 }
 
+void Widget::remove_action_group(const Glib::ustring& name)
+{
+  gtk_widget_insert_action_group(gobj(), name.c_str(), 0 /* see C docs */);
+}
+
 } // namespace Gtk
diff --git a/gtk/src/widget.hg b/gtk/src/widget.hg
index 73644d1..02f75a0 100644
--- a/gtk/src/widget.hg
+++ b/gtk/src/widget.hg
@@ -573,6 +573,15 @@ public:
   //but it is sometimes helpful to call it from outside:
   _WRAP_METHOD(void insert_action_group(const Glib::ustring& name, const Glib::RefPtr<Gio::ActionGroup>& 
group), gtk_widget_insert_action_group)
 
+  /** Removes a group from the widget.
+   * See insert_action_group().
+   * 
+   * @param name The prefix for actions.
+   *
+   * @newin{3,10}
+   */
+  void remove_action_group(const Glib::ustring& name);
+
   _WRAP_SIGNAL(void show(),"show")
   _WRAP_SIGNAL(void hide(),"hide", custom_c_callback)