[gtkmm] Range: Derived from (and implement) Orientable.

[Murray Cumming <murrayc src gnome org>]

commit b63bfb544ef185be5829540f473b721c84e67bf5
Author: Murray Cumming <murrayc murrayc com>
Date:   Mon Apr 24 11:51:20 2017 +0200

    Range: Derived from (and implement) Orientable.
    
    Because that's what GtkRange does.
    This also removes the Orientable base class from Scrollbar, because
    it now gets it via its Range base class.
    
    Bug #781655 (Daniel Boles)

 gtk/src/range.hg     |    7 ++++++-
 gtk/src/scrollbar.hg |    7 ++-----
 2 files changed, 8 insertions(+), 6 deletions(-)
---
diff --git a/gtk/src/range.hg b/gtk/src/range.hg
index 195e91f..fca85c5 100644
--- a/gtk/src/range.hg
+++ b/gtk/src/range.hg
@@ -18,6 +18,8 @@
 #include <gtkmm/widget.h>
 #include <gtkmm/enums.h> //For SensitivityType.
 #include <gtkmm/border.h>
+#include <gtkmm/orientable.h>
+
 _DEFS(gtkmm,gtk)
 _PINCLUDE(gtkmm/private/widget_p.h)
 
@@ -31,9 +33,12 @@ class Adjustment;
  *
  * @ingroup Widgets
  */
-class Range : public Widget
+class Range
+: public Widget,
+  public Orientable
 {
   _CLASS_GTKOBJECT(Range,GtkRange,GTK_RANGE,Gtk::Widget,GtkWidget)
+  _IMPLEMENTS_INTERFACE(Orientable)
 protected:
   _CTOR_DEFAULT
 public:
diff --git a/gtk/src/scrollbar.hg b/gtk/src/scrollbar.hg
index ec287b9..3c32b18 100644
--- a/gtk/src/scrollbar.hg
+++ b/gtk/src/scrollbar.hg
@@ -17,7 +17,6 @@
  */
 
 #include <gtkmm/range.h>
-#include <gtkmm/orientable.h>
 
 _DEFS(gtkmm,gtk)
 _PINCLUDE(gtkmm/private/range_p.h)
@@ -42,11 +41,9 @@ namespace Gtk
  * @ingroup Widgets
  */
 class Scrollbar
- : public Range,
-   public Orientable
-{
+ : public Range{
   _CLASS_GTKOBJECT(Scrollbar,GtkScrollbar,GTK_SCROLLBAR,Gtk::Range,GtkRange)
-  _IMPLEMENTS_INTERFACE(Orientable)
+
 public:
   _CTOR_DEFAULT()