Build 2 libs - one with Neon and one without, then merge them together.  Allows for a fat binary that runs on regular arm.
BUG=298
TESTED=untested
R=tomfinegan@chromium.org

Review URL: https://webrtc-codereview.appspot.com/5169005

git-svn-id: http://libyuv.googlecode.com/svn/trunk@951 16f28f9a-4ce2-e073-06de-1de4eb20be90