add support for probably RLE-compressed IFF DEEP

[ami_stuff]

The attached file was saved by TVPaint program and according to the specs "1" compression should be RLE.

http://ffmpeg.org/trac/ffmpeg/attachment/ticket/1045/DEEP.txt

Compressions currently defined:

NOCOMPRESSION	=	0
RUNLENGTH	=	1
HUFFMAN		=	2
DYNAMICHUFF	=	3
JPEG		=	4

C:\>ffmpeg -i tvpaint.deep
ffmpeg version N-38632-g4cda8aa Copyright (c) 2000-2012 the FFmpeg developers
  built on Mar  8 2012 02:38:08 with gcc 4.5.0 20100414 (Fedora MinGW 4.5.0-1.fc
14)
  configuration: --prefix=/var/www/users/research/ffmpeg/snapshots/build --arch=
x86 --target-os=mingw32 --cross-prefix=i686-pc-mingw32- --cc='ccache i686-pc-min
gw32-gcc' --enable-w32threads --enable-memalign-hack --enable-runtime-cpudetect
--enable-cross-compile --enable-static --disable-shared --extra-libs='-lws2_32 -
lwinmm' --extra-cflags='--static -I/var/www/users/research/ffmpeg/snapshots/buil
d/include' --extra-ldflags='-static -L/var/www/users/research/ffmpeg/snapshots/b
uild/lib' --enable-bzlib --enable-zlib --enable-gpl --enable-version3 --enable-n
onfree --enable-libx264 --enable-libspeex --enable-libtheora --enable-libvorbis
--enable-libfaac --enable-libxvid --enable-libopencore-amrnb --enable-libopencor
e-amrwb --enable-libmp3lame --enable-libvpx --disable-decoder=libvpx
  libavutil      51. 42.100 / 51. 42.100
  libavcodec     54. 10.100 / 54. 10.100
  libavformat    54.  2.100 / 54.  2.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 63.100 /  2. 63.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0.  7.100 /  0.  7.100
  libpostproc    52.  0.100 / 52.  0.100
tvpaint.deep: Invalid data found when processing input

[cehoyos]

Fixed by Peter Ross.