Backported PyCapsule from 3.1, and converted most uses of
CObject to PyCapsule.
diff --git a/Include/cobject.h b/Include/cobject.h
index 4e24d7d..e5e246b 100644
--- a/Include/cobject.h
+++ b/Include/cobject.h
@@ -6,6 +6,8 @@
    to other extension modules, so that extension modules can use the
    Python import mechanism to link to one another.
 
+   DEPRECATED - Use PyCapsule objects instead.
+                CObject will be removed in 2.8 (if there is one).
 */
 
 #ifndef Py_COBJECT_H