util+tests: fix copyright notices in files copied from NFD

Change-Id: I43fd6a6085cd5ffe99676e20d1cf55400577bdb7
diff --git a/src/util/notification-stream.hpp b/src/util/notification-stream.hpp
index e9921c0..d886173 100644
--- a/src/util/notification-stream.hpp
+++ b/src/util/notification-stream.hpp
@@ -1,6 +1,12 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2013-2017 Regents of the University of California.
+ * Copyright (c) 2014-2017 Regents of the University of California,
+ *                         Arizona Board of Regents,
+ *                         Colorado State University,
+ *                         University Pierre & Marie Curie, Sorbonne University,
+ *                         Washington University in St. Louis,
+ *                         Beijing Institute of Technology,
+ *                         The University of Memphis.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -19,32 +25,6 @@
  * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
  */
 
-/**
- * Original copyright notice from NFD:
- *
- * Copyright (c) 2014,  Regents of the University of California,
- *                      Arizona Board of Regents,
- *                      Colorado State University,
- *                      University Pierre & Marie Curie, Sorbonne University,
- *                      Washington University in St. Louis,
- *                      Beijing Institute of Technology,
- *                      The University of Memphis
- *
- * This file is part of NFD (Named Data Networking Forwarding Daemon).
- * See AUTHORS.md for complete list of NFD authors and contributors.
- *
- * NFD is free software: you can redistribute it and/or modify it under the terms
- * of the GNU General Public License as published by the Free Software Foundation,
- * either version 3 of the License, or (at your option) any later version.
- *
- * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
- * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
- * PURPOSE.  See the GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
- */
-
 #ifndef NDN_UTIL_NOTIFICATION_STREAM_HPP
 #define NDN_UTIL_NOTIFICATION_STREAM_HPP
 
@@ -55,7 +35,6 @@
 #include "concepts.hpp"
 
 namespace ndn {
-
 namespace util {
 
 /** \brief provides a publisher of Notification Stream
@@ -76,9 +55,7 @@
   }
 
   virtual
-  ~NotificationStream()
-  {
-  }
+  ~NotificationStream() = default;
 
   void
   postNotification(const Notification& notification)