buffersink: document special error codes returned from av_buffersink_get_frame
lavfi doxy: add buffer{src,sink}.h to the main lavfi doxy group
avcodec/vp8dsp: add VP7 idct and loop filter

Signed-off-by: Peter Ross <pross@xvid.org>
Reviewed-by: "Ronald S. Bultje" <rsbultje@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'f758ea6e99af6ebd24bbe222898a921c222e5593'

* commit 'f758ea6e99af6ebd24bbe222898a921c222e5593':
  buffersink: document special error codes returned from av_buffersink_get_frame

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  lavfi doxy: add buffer{src,sink}.h to the main lavfi doxy group

Conflicts:
	libavfilter/buffersink.h
	libavfilter/buffersrc.h

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/x86/lossless_videodsp: fix w type

Fixes fate issues on mingw64

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