ref: adding copyright headers and licensing files

Change-Id: I135f73159c3e010f7faf14f1215bbd74eb32c2cb
diff --git a/lib/exec/child.go b/lib/exec/child.go
index 77cff1c..cf2a141 100644
--- a/lib/exec/child.go
+++ b/lib/exec/child.go
@@ -1,3 +1,7 @@
+// Copyright 2015 The Vanadium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
 package exec
 
 import (