As a sample, this commit also includes a test suite for
ndn::ping::client::StatisticsCollector class.
refs #2795
Change-Id: Ia0c7522ae26bee1cc9d172c7379ab62f84325ed7
This is an exact copy of code from
ndn-tlv-ping:commit:d3675f528af468d59b2c505057acd21b56210c5c
refs #2525
Change-Id: I4cd93087cf28737fa109183e83aa3bcf60c0f6ff