Update ICU to 58.1

source/common/unicode/ucharstriebuilder.h

Index: source/common/unicode/ucharstriebuilder.h
diff --git a/source/common/unicode/ucharstriebuilder.h b/source/common/unicode/ucharstriebuilder.h
index 35e353d41b515eea8ff6ad972031501e21644f39..cc9fb77a9176e0e6bc921089e80c53901ccc1dc5 100644
--- a/source/common/unicode/ucharstriebuilder.h
+++ b/source/common/unicode/ucharstriebuilder.h
@@ -1,6 +1,8 @@
+// Copyright (C) 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
 /*
 *******************************************************************************
-*   Copyright (C) 2010-2014, International Business Machines
+*   Copyright (C) 2010-2016, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 *******************************************************************************
 *   file name:  ucharstriebuilder.h