ARGBQuantize to do a posterizing effect.  Added random resolution unittest.
BUG=none
TEST=none
Review URL: https://webrtc-codereview.appspot.com/654005

git-svn-id: http://libyuv.googlecode.com/svn/trunk@289 16f28f9a-4ce2-e073-06de-1de4eb20be90
12 files changed