goprotobuf: Use a standard redirecting AUTHORS and CONTRIBUTORS file.

Correct copyright notice to "The Go Authors" throughout.

R=rsc, bradfitz
CC=golang-dev
http://codereview.appspot.com/6845101
diff --git a/proto/equal.go b/proto/equal.go
index 11ea6ed..50f20d4 100644
--- a/proto/equal.go
+++ b/proto/equal.go
@@ -1,6 +1,6 @@
 // Go support for Protocol Buffers - Google's data interchange format
 //
-// Copyright 2011 Google Inc.  All rights reserved.
+// Copyright 2011 The Go Authors.  All rights reserved.
 // http://code.google.com/p/goprotobuf/
 //
 // Redistribution and use in source and binary forms, with or without