core: use markers in StatusDataset and NotificationStream

This commit also refactors FaceMonitor as generic NotificationSubscriber,
and refactors AutoregServer to use FaceMonitor.

refs #1837 #1838

Change-Id: I8b40dfae118853d1224c8290cf92e7cc0daa116f
diff --git a/daemon/mgmt/face-manager.cpp b/daemon/mgmt/face-manager.cpp
index c8bc267..b31f841 100644
--- a/daemon/mgmt/face-manager.cpp
+++ b/daemon/mgmt/face-manager.cpp
@@ -119,7 +119,7 @@
   , m_faceTable(faceTable)
   , m_faceStatusPublisher(m_faceTable, *m_face, FACES_LIST_DATASET_PREFIX, keyChain)
   , m_channelStatusPublisher(m_factories, *m_face, CHANNELS_LIST_DATASET_PREFIX, keyChain)
-  , m_notificationStream(m_face, FACE_EVENTS_PREFIX, keyChain)
+  , m_notificationStream(*m_face, FACE_EVENTS_PREFIX, keyChain)
   , m_signedVerbDispatch(SIGNED_COMMAND_VERBS,
                          SIGNED_COMMAND_VERBS +
                          (sizeof(SIGNED_COMMAND_VERBS) / sizeof(SignedVerbAndProcessor)))