BUG=348
TESTED=cpplint.py --filter=-readability/casting source/*.cc include/libyuv/*.h
R=tpsiaki@google.com

Review URL: https://webrtc-codereview.appspot.com/21209004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1048 16f28f9a-4ce2-e073-06de-1de4eb20be90