BUG=21,22
TEST=build\release\libyuv_unittest.exe  --gtest_filter=*
Review URL: https://webrtc-codereview.appspot.com/447013

git-svn-id: http://libyuv.googlecode.com/svn/trunk@218 16f28f9a-4ce2-e073-06de-1de4eb20be90