[gtkmm] Widget: Remove get/set_center_widget().

[Murray Cumming <murrayc src gnome org>]

commit 141d2bcf90aacb2f7e1c38aadd0cf59b7de1122b
Author: Murray Cumming <murrayc murrayc com>
Date:   Thu Apr 27 10:41:14 2017 +0200

    Widget: Remove get/set_center_widget().
    
    This was removed from the GtkWidget API:
    https://git.gnome.org/browse/gtk+/commit/?id=fb927d19935efe95130ebdbef14e458c71bac301

 gtk/src/box.ccg |    5 -----
 gtk/src/box.hg  |    9 ---------
 2 files changed, 0 insertions(+), 14 deletions(-)
---
diff --git a/gtk/src/box.ccg b/gtk/src/box.ccg
index 4c78ba4..5d6824e 100644
--- a/gtk/src/box.ccg
+++ b/gtk/src/box.ccg
@@ -39,9 +39,4 @@ void Box::pack_end(Widget& child, PackOptions options)
   gtk_box_pack_end(gobj(), child.gobj(), (gboolean)expand, (gboolean)fill);
 }
 
-void Box::unset_center_widget()
-{
-  gtk_box_set_center_widget(gobj(), nullptr);
-}
-
 } //namespace Gtk
diff --git a/gtk/src/box.hg b/gtk/src/box.hg
index 4cc1674..d83eb1c 100644
--- a/gtk/src/box.hg
+++ b/gtk/src/box.hg
@@ -117,15 +117,6 @@ public:
 
   _WRAP_METHOD(void reorder_child(Widget& child, int position), gtk_box_reorder_child)
 
-  _WRAP_METHOD(void set_center_widget(Widget& widget), gtk_box_set_center_widget)
-
-  /** Unset the center_widget.
-   * See set_center_widget().
-   */
-  void unset_center_widget();
-  _WRAP_METHOD(Widget* get_center_widget(), gtk_box_get_center_widget) //transfer none
-  _WRAP_METHOD(const Widget* get_center_widget() const, gtk_box_get_center_widget, constversion) //transfer 
none
-
   _WRAP_PROPERTY("spacing", int)
   _WRAP_PROPERTY("homogeneous", bool)
   _WRAP_PROPERTY("baseline-position", BaselinePosition)