[gtkmm] gtk-demo/demowindow: Order #includes correctly

[Daniel Boles <dboles src gnome org>]

commit 06b92a9badfe822148993db5165df66752fe7501
Author: Daniel Boles <dboles src gnome org>
Date:   Fri May 26 16:47:06 2017 +0100

    gtk-demo/demowindow: Order #includes correctly
    
    in the spirit of
    https://git.gnome.org/browse/gtk+/tree/docs/CODING-STYLE#n458
    
    “Every file must include config.h first, then its own header, then other
    GTK+ headers that it needs, then system and third-party headers that it
    needs.”
    
    For the “other GTK+ headers” part, I took the liberty of using the order
    I normally follow, which is GLib headers followed by GIO ones followed
    by GTK+ ones. I use this as it follows their order in the software stack

 demos/gtk-demo/demowindow.cc |   17 ++++++++++-------
 1 files changed, 10 insertions(+), 7 deletions(-)
---
diff --git a/demos/gtk-demo/demowindow.cc b/demos/gtk-demo/demowindow.cc
index 39bf983..a76ad51 100644
--- a/demos/gtk-demo/demowindow.cc
+++ b/demos/gtk-demo/demowindow.cc
@@ -19,17 +19,20 @@
 #include "config.h"
 #endif
 
-#include <gtkmm/cellrenderertext.h>
-#include <gtkmm/treeviewcolumn.h>
+#include "demowindow.h"
+
+#include "demos.h"
+#include "textwidget.h"
+
 #include <glibmm/bytes.h>
 #include <glibmm/convert.h>
 #include <giomm/resource.h>
-#include "demowindow.h"
-#include "textwidget.h"
-#include "demos.h"
-#include <iostream>
-#include <cstring>
+#include <gtkmm/cellrenderertext.h>
+#include <gtkmm/treeviewcolumn.h>
+
 #include <cstddef>
+#include <cstring>
+#include <iostream>
 
 using std::isspace;
 using std::strlen;