youtube-dl 2017.10.07

Core

• [YoutubeDL] Ignore duplicates in --playlist-items
• [YoutubeDL] Fix out of range --playlist-items for iterable playlists and
  reduce code duplication (#14425)

• [utils] Use cache in OnDemandPagedList by default

• [postprocessor/ffmpeg] Convert to opus using libopus (#14381)

Extractors

• [reddit] Sort formats (#14430)
• [lnkgo] Relax URL regular expression (#14423)
• [pornflip] Extend URL regular expression (#14405, #14406)

• [xtube] Add support for embed URLs (#14417)
• [xvideos] Add support for embed URLs and improve extraction (#14409)

• [beeg] Fix extraction (#14403)
• [tvn24] Relax URL regular expression (#14395)
• [nbc] Fix extraction (#13651, #13715, #14137, #14198, #14312, #14314, #14378,
  #14392, #14414, #14419, #14431)

• [ketnet] Add support for videos without direct sources (#14377)

• [canvas] Generalize mediazone.vrt.be extractor and rework canvas and een

• [afreecatv] Add support for adult videos (#14376)