UNTESTED: expand getVideoChunksPlaylist to look for quality

first step towards resolving #81.

old broadcasts *can* have multiple resolutions, see https://api.twitch.tv/api/videos/c5039141

thisdoes not respect `maxQuality` like it should. on the other hand, `saveHLSToPlaylist` does not as well.

while there is `_bestMatchForChosenQuality` it won't work in those cases, how quality is handled needs to be reworked in all those functions to have a single choosing or ordering function (which returns a list like [choosen | best<maxQuality | nextBest<maxQuality|...]