use strict in the utils/ too

utils/cffStandardStrings.js

@@ -1,3 +1,8 @@
+/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- /
+/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
+
+"use strict";
+
 var CFFStrings = [
   ".notdef",
   "space",

utils/fonts_utils.js

@@ -1,3 +1,8 @@
+/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- /
+/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
+
+"use strict";
+
 /**
  * The Type2 reader code below is only used for debugging purpose since Type2
  * is only a CharString format and is never used directly as a Font file.