lavfi: add Bauer stereo-to-binaural audio filter

Signed-off-by: Anton Khirnov <anton@khirnov.net>
matroskaenc: write CodecDelay
matroska: add the Opus mapping
Merge commit '1c0210c7981b6a61043d9171f506b435ff5a1f5e'

* commit '1c0210c7981b6a61043d9171f506b435ff5a1f5e':
  lavfi: add Bauer stereo-to-binaural audio filter

Conflicts:
	Changelog
	configure
	doc/filters.texi
	libavfilter/Makefile
	libavfilter/allfilters.c
	libavfilter/version.h

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'a1aa37dd0b96710d4a17718198a3f56aea2040c1'

* commit 'a1aa37dd0b96710d4a17718198a3f56aea2040c1':
  matroskaenc: write CodecDelay

Conflicts:
	libavformat/matroskaenc.c
	tests/ref/lavf/mkv
	tests/ref/seek/lavf-mkv

This is largely not merged as it causes assertion failures and av sync errors
Further investigation of this is warranted if the changes are found to
fix/improve something in relation to d92b1b1babe69268971863649c225e1747358a74

See: d92b1b1babe69268971863649c225e1747358a74
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '141fdc763c2841b572d29a2ad78513e8d5325870'

* commit '141fdc763c2841b572d29a2ad78513e8d5325870':
  matroska: add the Opus mapping

Conflicts:
	libavformat/matroska.c

See: 30549294ef0f796d48b1ffa482bd9315d4dbb83c
Merged-by: Michael Niedermayer <michaelni@gmx.at>
avformat/vobsub: remove pointless FAIL macro.
avformat/vobsub: use av_make_q().