/g 0.66
/l playing

//DONE reset currentTime, duration, index in players' stopVideo
//DONE show correct duration in soundcloud playlist
//TODO implement native play/pause toggle in vimeo
//TODO add console.log in error, next
//TODO pass all data variables from observer to observable
//TODO put default volume somewhere else than in abstract
//TODO use after to callback to observer
//TODO use playing: null to play first track
//TODO check how players behave when loadVideo different players fast