bugfixes
- bufferController/levelHelper: protect against TypeError
- stream-controller: Ignore startDTS when it is NaN in onFragLoaded #581
- Comment between EXTINF and segment URL breaks playback #555
improvement
- Add type and version to level object #547
- xhr-loader: don't retry if HTTP status code between 400 and 499,these errors are not recoverable. retrying is useless