As a sample, this commit also includes a test suite for
ndn::ping::client::StatisticsCollector class.
refs #2795
Change-Id: Ia0c7522ae26bee1cc9d172c7379ab62f84325ed7
Code is copied from ndndump:commit:c266031924d723b9a73be29ebb66fd6db26aade5,
with minor changes for removing trailing whitespaces.
Build script is rewritten.
refs #2692
Change-Id: I07eec2f87542f1328b851cc2c4e5c9b6279db7da