jls: support lossy pal1-7

[ami_stuff]

​http://www.datafilehost.com/d/97482c46

C:\>ffmpeg -i 128_lossy_1.jls out.bmp
ffmpeg version N-71042-g83020f8 Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 4.9.2 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --
enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-lib
modplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrw
b --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinge
r --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --en
able-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis
 --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-
libx265 --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enab
le-zlib
  libavutil      54. 20.100 / 54. 20.100
  libavcodec     56. 29.100 / 56. 29.100
  libavformat    56. 26.101 / 56. 26.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 13.101 /  5. 13.101
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  3.100 / 53.  3.100
run overflow
Input #0, jpegls_pipe, from '128_lossy_1.jls':
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: jpegls, pal8(7 bpc, bt470bg/unknown/unknown), 640x480, 2
5 tbr, 25 tbn, 25 tbc
Output #0, image2, to 'out.bmp':
  Metadata:
    encoder         : Lavf56.26.101
    Stream #0:0: Video: bmp, pal8(7 bpc), 640x480, q=2-31, 200 kb/s, 25 fps, 25
tbn, 25 tbc
    Metadata:
      encoder         : Lavc56.29.100 bmp
Stream mapping:
  Stream #0:0 -> #0:0 (jpegls (native) -> bmp (native))
Press [q] to stop, [?] for help
run overflow
frame=    1 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A
video:301kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing o
verhead: unknown