Add AUTHORS file for copyright tracking

BUG=skia:
R=jcgregorio@google.com, rmistry@google.com

Author: hcm@google.com

Review URL: https://codereview.chromium.org/138413004

git-svn-id: http://skia.googlecode.com/svn/trunk@13117 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed