Merge remote-tracking branch 'lukaszmluki/master'

* lukaszmluki/master:
  lavc: use av_fifo_freep
  lavf: use av_fifo_freep
  ffmpeg: use av_fifo_freep
  lavd/jack_audio: use av_fifo_freep
  lavfi: use av_fifo_freep
  lavu/fifo: add av_fifo_freep function

Merged-by: Michael Niedermayer <michaelni@gmx.at>