Add myself to 'AUTHORS' and 'CONTRIBUTORS'

R=rsc, r
https://golang.org/cl/154175
diff --git a/AUTHORS b/AUTHORS
index cf165d8..c753415 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -9,6 +9,7 @@
 # Please keep the list sorted.
 
 Abhinav Gupta <abhinav.g90@gmail.com>
+Aron Nopanen <aron.nopanen@gmail.com>
 David G. Andersen <dave.andersen@gmail.com>
 David Titarenco <david.titarenco@gmail.com>
 Devon H. O'Dell <devon.odell@gmail.com>