Gtk: New Global.custom file to bring some overloads from Hyena

Hyena has bindings to gtk_show_uri. Now that gtk-sharp binds
this API targeting 3.x, we can bring the extra overloads from
hyena and mark them as obsolete there.

gtk/Global.custom

@@ -0,0 +1,29 @@
+//  Gtk.Global.custom - Gtk Global customizations
+//
+//  Authors:  Aaron Bockover <abockover@novell.com>
+// 
+//  Copyright 2007-2010 Novell, Inc.
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of version 2 of the Lesser GNU General
+// Public License as published by the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this program; if not, write to the
+// Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+// Boston, MA 02111-1307, USA.
+
+		public static bool ShowUri (string uri)
+		{
+			return ShowUri (null, uri);
+		}
+
+		public static bool ShowUri (Gdk.Screen screen, string uri)
+		{
+			return ShowUri (screen, uri, Gtk.Global.CurrentEventTime);
+		}