Enable HTML-rendered captions in all browsers
Created by: TobbeMobiTV
The full-screen HTML rendering of subtitles is working in IE11 from #797. Thus we can now enable this rendering in IE11. It also works in Edge similarly to IE11, so the IE11 test was extended to Edge. Fixes #748 (closed).
Also made a fix to the sample captioning apps which repeated subtitle tracks because they listened to the wrong event.