Merge remote-tracking branch 'qatar/master'

* qatar/master:
  matroska: Clear prev_pkt between seeks.
  avutil: change default buffer size alignment for sample buffer functions
  audemux: Add a sanity check for the number of channels
  Remove libdirac decoder.
  matroska: Add incremental parsing of clusters.
  avconv: fix off by one check in complex_filter
  mpegts: Try seeking back even for nonseekable protocols
  swscale: K&R formatting cosmetics (part III)

Conflicts:
	configure
	doc/general.texi
	doc/platform.texi
	ffmpeg.c
	libavcodec/Makefile
	libavcodec/allcodecs.c
	libavcodec/libdirac.h
	libavcodec/libdiracdec.c
	libavformat/au.c
	libavformat/mpegts.c
	libswscale/input.c
	tests/ref/seek/lavf_mkv

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