tmp (wokkel/rsm): various improvments:

- restored original tmp.wokkel.pubsub.PubSubService._toResponse_items
    - changed arguments order in RSMRequest.__init__ to have most common arguments first
    - added __str__ methods
    - better parsing/toElement
    - better handling of optional elements/attributes (count/index)
    - _toResponse_items handler RSM set elements without modifying original pubsub _toResponse_items
    - renamed parse to fromElement for coherency

src/tmp/wokkel/pubsub.py

@@ -1408,12 +1408,8 @@ class PubSubService(XMPPHandler, IQHandlerMixin):
         items["node"] = request.nodeIdentifier
 
         for item in result:
-            if isinstance(item, tuple):
-                # XXX: see sat_pubsub.pgsql_storage.LeafNode.getItemsById return value
-                item = item[0]
-            if item.name == 'item':
-                item.uri = NS_PUBSUB
-                items.addChild(item)
+            item.uri = NS_PUBSUB
+            items.addChild(item)
 
         return response