Warming up: Make acquisition wrappers have __parent__ in addition to aq_parent

(they point to the same thing).

_Acquisition.c

@@ -419,8 +419,18 @@ Wrapper_findattr(Wrapper *self, PyObject *oname,
   char *name="";
 
   if (PyString_Check(oname)) name=PyString_AS_STRING(oname);
-  if (*name=='a' && name[1]=='q' && name[2]=='_')
-    if ((r=Wrapper_special(self, name+3, oname)))
+
+  /* handle aq_ and __parent__ attributes */
+  if ((*name=='a' && name[1]=='q' && name[2]=='_') ||
+      (strcmp(name, "__parent__")==0)) {
+
+    /* __parent__ is an alias to aq_parent */
+    if (strcmp(name, "__parent__")==0)
+      name = "parent";
+    else
+      name = name + 3;
+
+    if ((r=Wrapper_special(self, name, oname)))
       {
         if (filter)
           switch(apply_filter(filter,OBJECT(self),oname,r,extra,orig))
@@ -431,6 +441,7 @@ Wrapper_findattr(Wrapper *self, PyObject *oname,
         else return r;
       }
     else PyErr_Clear();
+  }
   else if (*name=='_' && name[1]=='_' && 
            (strcmp(name+2,"reduce__")==0 ||
             strcmp(name+2,"reduce_ex__")==0 ||