Add fix for playlist not updating when only endList changes

[hpate-omicron]

Description

See videojs/videojs-contrib-hls#1424

Possibly related issues:
#442
#550
#555
#111

Specific Changes proposed

This updates the logic for deciding whether a playlist has changed to check the endList property as well.

Requirements Checklist

• Feature implemented / Bug fixed
• If necessary, more likely in a feature request than a bug fix
  • Unit Tests updated or fixed
  • Docs/guides updated
  • Example created (starter template on JSBin)
• Reviewed by Two Core Contributors

[gesinger]

Minor note that we can update the comment above the code.

// consider the playlist unchanged if the number of segments is equal and the media
// sequence number is unchanged

But otherwise looks good to me, and thank you for the PR!

[hpate-omicron]

Oops, missed that, I've updated the comment and rebased :)

[forbesjo]

Thank you for your PR but we will not be accepting new changes for this repo and will be archived very soon. I would advise you to open your PR against the next iteration of this project at https://github.com/videojs/http-streaming.