NFD+model+apps+helper+tests: Upgrade NFD and related changes

Based on NFD:commit:2fc649bfc67b93b4191cfbee5bcd70330bfb48f0 (version 0.3.4)

Change-Id: I89f5182600467171797af4f8f83e1edffe14ad95
Refs: #3125
diff --git a/apps/ndn-app.hpp b/apps/ndn-app.hpp
index 8ba90d3..57dda58 100644
--- a/apps/ndn-app.hpp
+++ b/apps/ndn-app.hpp
@@ -99,11 +99,8 @@
   StopApplication(); ///< @brief Called at time specified by Stop
 
 protected:
-  bool m_active; ///< @brief Flag to indicate that application is active (set by StartApplication
-  /// and StopApplication)
-  shared_ptr<Face>
-    m_face; ///< @brief automatically created application face through which application
-  /// communicates
+  bool m_active; ///< @brief Flag to indicate that application is active (set by StartApplication and StopApplication)
+  shared_ptr<AppFace> m_face; ///< @brief automatically created application face through which application communicates
 
   TracedCallback<shared_ptr<const Interest>, Ptr<App>, shared_ptr<Face>>
     m_receivedInterests; ///< @brief App-level trace of received Interests