implement macroblock types B_16x8, B_8x16
tweak thresholds for comparing B mb types git-svn-id: svn://svn.videolan.org/x264/trunk@72 df754926-b1dd-0310-bc7b-ec298dee348c
tweak thresholds for comparing B mb types git-svn-id: svn://svn.videolan.org/x264/trunk@72 df754926-b1dd-0310-bc7b-ec298dee348c