Moving some logic of dealing with sequence numbers to SyncAppDataFetch

Adding recursive mutexes to SyncLogic, so hopefully it is now thread-safe

Small modification of publishing/retrieval names. Now session ID is
appended by SyncAppDataFetch / SyncAppDataPublish
diff --git a/model/sync-full-state.h b/model/sync-full-state.h
index 2aac7b9..5b80aff 100644
--- a/model/sync-full-state.h
+++ b/model/sync-full-state.h
@@ -67,7 +67,7 @@
   getDigest ();
   
   // from State
-  virtual bool
+  virtual boost::tuple<bool/*inserted*/, bool/*updated*/, SeqNo/*oldSeqNo*/>
   update (NameInfoConstPtr info, const SeqNo &seq);
 
   virtual bool