* qatar/master: (22 commits)
  rv40dsp x86: use only one register, for both increment and loop counter
  rv40dsp: implement prescaled versions for biweight.
  avconv: use default channel layouts when they are unknown
  avconv: parse channel layout string
  nutdec: K&R formatting cosmetics
  vda: Signal 4 byte NAL headers to the decoder regardless of what's in the extradata
  mem: Consistently return NULL for av_malloc(0)
  vf_overlay: implement poll_frame()
  vf_scale: support named constants for sws flags.
  lavc doxy: add all installed headers to doxy groups.
  lavc doxy: add avfft to the main lavc group.
  lavc doxy: add remaining avcodec.h functions to a misc doxygen group.
  lavc doxy: add AVPicture functions to a doxy group.
  lavc doxy: add resampling functions to a doxy group.
  lavc doxy: replace \ with /
  lavc doxy: add encoding functions to a doxy group.
  lavc doxy: add decoding functions to a doxy group.
  lavc doxy: fix formatting of AV_PKT_DATA_{PARAM_CHANGE,H263_MB_INFO}
  lavc doxy: add AVPacket-related stuff to a separate doxy group.
  lavc doxy: add core functions/definitions to a doxy group.
  ...

Conflicts:
	ffmpeg.c
	libavcodec/avcodec.h
	libavcodec/vda.c
	libavcodec/x86/rv40dsp.asm
	libavfilter/vf_scale.c
	libavformat/nutdec.c
	libavutil/mem.c
	tests/ref/acodec/pcm_s24daud
Merged-by: Michael Niedermayer <michaelni@gmx.at>