add unit test, use md5 and psnr to test the validity of decode.

usage:
./unit_test.sh  /root/Videos/h264/Base_Ext_Main_profile/
./unit_test.sh  /root/Videos/vp8/vp8/
./unit_test.sh  /root/Videos/jpg/workdir.jpeg_dec/ /root/Videos/jpg/yuv/
by default, yami decode create output file name by apend "_widthxheight.fourcc"; guess resolution from it make things easier.

you can also add width/height in command line option to override such guess.