plugins.disney_de: Minor tweaks and fixes.
plugins.disney_de: Minor tweaks and fixes.

- Remove unnecessary headers.
- Fix Python 3 compatiblity.

chhe/livestreamer,programming086/livestreamer,back-to/streamlink,programming086/livestreamer,bastimeyer/streamlink,intact/livestreamer,flijloku/livestreamer,mmetak/streamlink,Saturn/livestreamer,wlerin/streamlink,ethanhlc/streamlink,ethanhlc/streamlink,gravyboat/streamlink,chhe/streamlink,Dobatymo/livestreamer,chrippa/livestreamer,Feverqwe/livestreamer,Dobatymo/livestreamer,okaywit/livestreamer,Saturn/livestreamer,chrippa/livestreamer,okaywit/livestreamer,sbstp/streamlink,hmit/livestreamer,hmit/livestreamer,flijloku/livestreamer,streamlink/streamlink,caorong/livestreamer,blxd/livestreamer,streamlink/streamlink,javiercantero/streamlink,melmorabity/streamlink,gtmanfred/livestreamer,wolftankk/livestreamer,beardypig/streamlink,mmetak/streamlink,chhe/livestreamer,derrod/livestreamer,jtsymon/livestreamer,blxd/livestreamer,jtsymon/livestreamer,javiercantero/streamlink,wlerin/streamlink,wolftankk/livestreamer,gtmanfred/livestreamer,Feverqwe/livestreamer,intact/livestreamer,fishscene/streamlink,gravyboat/streamlink,bastimeyer/streamlink,Masaz-/livestreamer,melmorabity/streamlink,fishscene/streamlink,lyhiving/livestreamer,charmander/livestreamer,Klaudit/livestreamer,beardypig/streamlink,derrod/livestreamer,back-to/streamlink,charmander/livestreamer,Klaudit/livestreamer,lyhiving/livestreamer,chhe/streamlink,sbstp/streamlink,caorong/livestreamer,Masaz-/livestreamer