gobject: Add GBinding

GBinding is a simple, opaque object that represents a binding between a
property on a GObject instance (source) and property on another GObject
instance (target).

https://bugzilla.gnome.org/show_bug.cgi?id=348080

docs/reference/gobject/gobject-docs.sgml

@@ -83,6 +83,7 @@
       <xi:include href="xml/signals.xml" />
       <xi:include href="xml/gclosure.xml" />
       <xi:include href="xml/value_arrays.xml" />
+      <xi:include href="xml/gbinding.xml" />
   </reference>
   <reference label="III">
     <title>Tools Reference</title>

docs/reference/gobject/gobject-sections.txt

@@ -839,3 +839,26 @@ g_closure_get_type
 g_io_channel_get_type
 g_io_condition_get_type
 </SECTION>
+
+<SECTION>
+<FILE>gbinding</FILE>
+GBinding
+GBindingFlags
+g_binding_get_source
+g_binding_get_source_property
+g_binding_get_target
+g_binding_get_target_property
+g_binding_get_flags
+<SUBSECTION>
+g_object_bind_property
+GBindingTransformFunc
+g_object_bind_property_full
+<SUBSECTION Standard>
+G_TYPE_BINDING
+G_TYPE_BINDING_FLAGS
+G_BINDING
+G_IS_BINDING
+<SUBSECTION Private>
+g_binding_flags_get_type
+g_binding_get_type
+</SECTION>

docs/reference/gobject/gobject.types

@@ -1,6 +1,7 @@
 #include <glib/glib-object.h>
 #include "gobject.cI"
 
+g_binding_get_type
 g_object_get_type
 g_type_module_get_type
 g_type_plugin_get_type