ARMv6 optimized Intra4x4 prediction

Added ARM optimized intra 4x4 prediction
 - 2x faster on Profiler compared to C-code compiled with -O3
 - Function interface changed a little to improve BLOCKD structure
   access

Change-Id: I9bc2b723155943fe0cf03dd9ca5f1760f7a81f54
12 files changed