docs: Update authors information and add missing COPYING

Change-Id: I4ddc088fad850b44dd91c64d7ba1f60f91dba3ce
diff --git a/AUTHORS.md b/AUTHORS.md
index 02ce1d8..76fd14d 100644
--- a/AUTHORS.md
+++ b/AUTHORS.md
@@ -5,10 +5,13 @@
 
 * Xiaoke Jiang          <http://netarchlab.tsinghua.edu.cn/~shock/>
 * Alexander Afanasyev   <http://lasr.cs.ucla.edu/afanasyev/index.html>
-* Jiewen Tan            <alanwake@ucla.edu>
+* Yumin Xia             <me@yumin-xia.com>
 
 ## All project authors and contributors
 
 The following is an inevitably incomplete list of MUCH-APPRECIATED CONTRIBUTORS,
 people who have reported bugs, submitted patches, and implemented new features
 in the library:
+
+* Eric Newberry         <http://ericnewberry.com/>
+* Jiewen Tan            <alanwake@ucla.edu>