google_analytics.js: add tracking for playback fixes #390
google_analytics.js: add tracking for playback fixes #390

dayvson/clappr,dayvson/clappr,flavioribeiro/clappr,clappr/clappr,dayvson/clappr,clappr/clappr,flavioribeiro/clappr,clappr/clappr,flavioribeiro/clappr