h263i: support advanced prediction

[ami_stuff]

there are visibe graphic artifacts

C:\>ffmpeg -i advanced_prediction.avi out.avi
ffmpeg version N-40511-g66337bf Copyright (c) 2000-2012 the FFmpeg developers
  built on May  9 2012 02:38:42 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. 50.100 / 51. 50.100
  libavcodec     54. 21.100 / 54. 21.100
  libavformat    54.  4.100 / 54.  4.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 72.105 /  2. 72.105
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 11.100 /  0. 11.100
  libpostproc    52.  0.100 / 52.  0.100
Input #0, avi, from 'advanced_prediction.avi':
  Duration: 00:00:12.64, start: 0.000000, bitrate: 756 kb/s
    Stream #0:0: Video: h263i (I263 / 0x33363249), yuv420p, 320x240, 23.97 tbr,
23.97 tbn, 23.97 tbc
w:320 h:240 pixfmt:yuv420p tb:1/1000000 sar:0/1 sws_param:flags=2
Output #0, avi, to 'out.avi':
  Metadata:
    ISFT            : Lavf54.4.100
    Stream #0:0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 320x240, q=2-31, 200
 kb/s, 23.97 tbn, 23.97 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (h263i -> mpeg4)
Press [q] to stop, [?] for help
frame=   85 fps=0.0 q=5.1 size=     163kB time=00:00:03.54 bitrate= 376.9kbits/s
frame=  224 fps=0.0 q=6.6 size=     334kB time=00:00:09.34 bitrate= 293.0kbits/s
frame=  303 fps=239 q=4.5 Lsize=     418kB time=00:00:12.64 bitrate= 270.9kbits/
s
video:405kB audio:0kB global headers:0kB muxing overhead 3.160264%