Merge remote-tracking branch 'qatar/master'

* qatar/master:
  libspeexenc: add supported sample rates and channel layouts.
  Replace usleep() calls with av_usleep()
  lavu: add av_usleep() function
  utvideo: mark interlaced frames as such
  utvideo: Fix interlaced prediction for RGB utvideo.
  cosmetics: do not use full path for local headers
  lavu/file: include unistd.h only when available
  configure: check for unistd.h
  log: include unistd.h only when needed
  lavf: include libavutil/time.h instead of redeclaring av_gettime()

Conflicts:
	configure
	doc/APIchanges
	ffmpeg.c
	ffplay.c
	libavcodec/utvideo.c
	libavutil/avutil.h

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