* commit '129bb238':
  lavfi: add a slice threading infrastructure

Conflicts:
	Changelog
	cmdutils.c
	doc/APIchanges
	libavfilter/Makefile
	libavfilter/avfilter.c
	libavfilter/avfilter.h
	libavfilter/avfiltergraph.c
	libavfilter/internal.h
	libavfilter/version.h
Merged-by: Michael Niedermayer <michaelni@gmx.at>