Merge commit '194be1f4'

* commit '194be1f4':
  lavf: switch to AVStream.time_base as the hint for the muxer timebase

Conflicts:
	doc/APIchanges
	libavformat/filmstripenc.c
	libavformat/movenc.c
	libavformat/mxfenc.c
	libavformat/oggenc.c
	libavformat/swf.h
	libavformat/version.h
	tests/ref/lavf/mkv

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