Fix transcoding runtime errors.
Add hardware acceleration toggle for recent ffmpeg versions
Add NZBGet documentation
Merge pull request #507 from roderickvd/nightly

Fix transcoding runtime errors and add ffmpeg hardware acceleration
Fix and improve subtitle extraction

* Fix runtime error when extracting with duplicate = 0
* Only extract subtitles in the allowed language list
* Do not add subtitle language suffix when there is only one subtitle
  (this helps auto-detection of subtitles on many media players)
Merge pull request #512 from roderickvd/nightly

Fix and improve subtitle extraction
add xbox default. Fixes #513. Minor fix to subs extract. #512
move external subs after transcoding.
fix extraction of subtitle stream without language tag
ensure null strings create empty lists. Fixes #513
Merge pull request #514 from roderickvd/nightly

fix extraction of subtitle stream without language tag
don't pass None values. Fixes https://github.com/RuudBurger/CouchPotatoServer/issues/3725
Merge branch 'nightly' of https://github.com/clinton-hall/nzbToMedia into nightly
Fix subtitle extraction with multiple streams

Use the index position of the subtitle stream in the container, not in the array.
It is not guaranteed that the array order or size is the same as in the container.
This may be the case if we filtered out certain languages or hdmv_pgs_subtitle streams.
Merge pull request #516 from roderickvd/nightly

Fix subtitle extraction with multiple streams
don't copy if we are forcing FR or Resolution. Fixes #513
Merge branch 'nightly' of https://github.com/clinton-hall/nzbToMedia into nightly
Fix filtering of hdmv_pgs_subtitle subtitles on newer ffmpeg versions
Merge pull request #520 from roderickvd/nightly

Fix filtering of hdmv_pgs_subtitle subtitles on newer ffmpeg versions
use avprobe. Fixes #503 and don't link single files for NZB. Fixes #519