Move the NDNPing wrapper method to a helper class.

Also updates GPL header for the current calendar year.

Refs: #3492

Change-Id: Ic4977c33edd0311b140e6db3688afbb182acec9e
diff --git a/ndn/apps/ndn_ping_client.py b/ndn/apps/ndn_ping_client.py
new file mode 100644
index 0000000..7e7ff2a
--- /dev/null
+++ b/ndn/apps/ndn_ping_client.py
@@ -0,0 +1,43 @@
+# -*- Mode:python; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+#
+# Copyright (C) 2015-2018, The University of Memphis,
+#                          Arizona Board of Regents,
+#                          Regents of the University of California.
+#
+# This file is part of Mini-NDN.
+# See AUTHORS.md for a complete list of Mini-NDN authors and contributors.
+#
+# Mini-NDN 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.
+#
+# Mini-NDN 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 Mini-NDN, e.g., in COPYING.md file.
+# If not, see <http://www.gnu.org/licenses/>.
+
+import time
+
+class NDNPingClient:
+    @staticmethod
+    def ping(source, dest, nPings=1, interval=None, timeout=None, starting_seq_num=None,
+             identifier=None, allow_stale_data=False, print_timestamp=True, sleepTime=0.2):
+        print("Scheduling ping(s) from {} to {}".format(source.name, dest.name))
+        # Use "&" to run in background and perform parallel pings
+        source.cmd("ndnping{1}{2}{3}{4}{5}{6}{7} /ndn/{0}-site/{0} >> ping-data/{0}.txt &"
+        .format(
+            dest,
+            " -c {}".format(nPings),
+            " -i {}".format(interval) if interval else "",
+            " -o {}".format(timeout) if timeout  else "",
+            " -n {}".format(starting_seq_num) if starting_seq_num else "",
+            " -p {}".format(identifier) if identifier else "",
+            " -a" if allow_stale_data else "",
+            " -t" if print_timestamp else ""
+        ))
+        time.sleep(sleepTime)
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