Reattach event listeners to new video

[seandlg]

findVideoInterval is currently used to attach to a video. This relies on setInterval. What other mechanism could be used to attach to a video, that works on reactive Websites? When should look for a new video? Is there some generic event we can listen for, that will tell us when our current video gets unusable (in which case we scan for a new video)?

• Reattach to video; particularly interesting for websites such as Netflix, Amazon Prime Video etc. where a new episodes launches and we want to stay in the same party
• Find out what event best justifies rescanning for a new video

[seandlg]

It turns out that emptied is the correct event to listen to on the HTML5 video. A fix has already been applied.