Merge commit 'b08569a23948db107e5e6175cd4c695427d5339d'

      * commit 'b08569a23948db107e5e6175cd4c695427d5339d':
  lavf: Replace the ASF demuxer

Conflicts:
	Changelog
	libavformat/asf.h
	libavformat/asfdec.c
	libavformat/version.h
	tests/ref/fate/wmv8-drm-nodec
	tests/ref/seek/lavf-asf

The rewritten demuxer is placed in a new file, the current demuxer is
left as default. Carl has tested both and the one working better is
default.

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