Merge commit 'f0b234ab'

* commit 'f0b234ab':
  avformat: AviSynth demuxer rewrite

Conflicts:
	configure
	libavformat/avisynth.c

See: b9ad0094 (as well as later commits)
Merged-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/avisynth.c

 /*
- * Avi/AvxSynth support
+ * AviSynth/AvxSynth support
  * Copyright (c) 2012 AvxSynth Team.
  *
  * This file is part of FFmpeg