Several fixes

  - User playlists should now list correctly (fixed a race condition)
  - Livestream types can autoplay (no longer stuck at currentTime = -3)
  - Playlist items with NaN duration do not break user playlist saving
  - ffmpeg support can handle live media (e.g. icecast)
  - Invalid volume is sanitized and an error message is added
  - JWPlayer displays correctly for both HTML5 and Flash
  - JWPlayer volume synchronization is fixed
  - <audio> and <video> tags are scaled correctly with .embed-responsive-item
Merge branch '3.0' of github.com:calzoneman/sync into 3.0