Betterttv: Preserve srcset / 2x subscriber loyalty badges on hidpi screens

[tmtrademark]

Howdy.

Now that loyalty badges are a thing, it would be great if BTTV preserved or implemented the higher resolution icons on hidpi screens. Currently when BTTV creates the subscriber_badges <style> element in helpers.js it just uses the 1x version of the image. Can a media query be added to use the other images as well?

[EhsanKia]

That's my bad. I was lazy when I implemented the badge api and only included 1x.
I'll add 2x and 3x support.