Use labels from DASH manifest AdaptationSet
Created by: sevagsim
Purpose
Allow "Label" to be passed into the DASH manifest AdaptationSet. This will allow human readable labels for things like caption tracks and audio tracks.
See DASH IOP 4.3 here https://dashif.org/docs/DASH-IF-IOP-v4.3.pdf (page 35)
Sample manifest: https://s3-us-west-1.amazonaws.com/sev-a-g/ed.mpd