Add support for AVI RAW (YV16)

[ami_stuff]

The attached patch adds support for YV16 FourCC.

The sample file comes from:

 https://trac.videolan.org/vlc/ticket/4985

C:\>ffmpeg -i "4_2_2 planar YCbCr (YV16).avi"
ffmpeg version N-30956-g81ef892, Copyright (c) 2000-2011 the FFmpeg developers
  built on Jun 22 2011 17:34:15 with gcc 4.5.3
  configuration: --enable-gpl --enable-version3 --enable-memalign-hack --enable-
runtime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libo
pencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --
enable-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger
 --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libvpx --enabl
e-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  libavutil    51.  9. 1 / 51.  9. 1
  libavcodec   53.  7. 0 / 53.  7. 0
  libavformat  53.  4. 0 / 53.  4. 0
  libavdevice  53.  1. 1 / 53.  1. 1
  libavfilter   2. 23. 0 /  2. 23. 0
  libswscale    2.  0. 0 /  2.  0. 0
  libpostproc  51.  2. 0 / 51.  2. 0

Seems stream 0 codec frame rate differs from container frame rate: 15.00 (100000
0000/66667391) -> 15.00 (15/1)
Input #0, avi, from '4_2_2 planar YCbCr (YV16).avi':
  Duration: 00:00:03.53, start: 0.000000, bitrate: 19341 kb/s
    Stream #0.0: Video: YV16 / 0x36315659, 350x230, 15 fps, 15 tbr, 15 tbn, 15 tbc
At least one output file must be specified

[cehoyos]

Pushed, thank you!