Fixes an issue in native Safari and Android HLS playback where liveCurrentTime returns Infinity (as we don't have a seekableEnd or seekableEnd is actually Infinity). Which causes the new live ui to show up when we don't really have a live window.
Instead of returning Infinity when liveCurrentTime is Infinity, return 0. So that everything knows that we do not have a seekable window of live playback.
- Make sure that we seek to live playback on the first timeupdate
- Do not report that we are not live before playback has started (a timeupdate has been seen)
- Prevent negative seekable increments
- We can seek past the seekable value in the video element, so we use that to seek to live, rather than waiting for a seekable end change.
When liveui is enabled, allow seeking during the live window, add button that allows you to seek to the live edge and that indicates whether you are at the live edge or not.
