Add support for basic play counting
Add support for basic play counting

* By default, a play is counted when the video has played for at least 10% of
  the total video length.
* The 10% can be overridden by a different percentage or number of seconds.
* The timer will stop when the video is paused and resume when it is played.
* The timer uses "real" time, not video time, so seeking through a video will
  not increase the play time.
* If a video is restarted after a "play" is counted, it can receive an
  additional play (in case someone watches a video multiple times).

npafundi/videojs-playcount,npafundi/videojs-playcount,npafundi/videojs-playcount