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-app-socket.cc b/model/sync-app-socket.cc
index d703e76..3dca250 100644
--- a/model/sync-app-socket.cc
+++ b/model/sync-app-socket.cc
@@ -33,7 +33,8 @@
   , m_fetcher (m_ccnxHandle, dataCallback)
   , m_publisher (m_ccnxHandle)
   , m_syncLogic (syncPrefix,
-                 bind (&AppDataFetch::fetch, m_fetcher, _1, _2, _3),
+                 bind (&AppDataFetch::onUpdate, m_fetcher, _1, _2, _3),
+                 bind (&AppDataFetch::onRemove, m_fetcher, _1),
                  m_ccnxHandle)
 {
 }