fixes #131, use before define from variables to classes

lib/src/js/printer.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of js_ast;
 
 
 class JavaScriptPrintingOptions {
   final bool shouldCompressOutput;
   final bool minifyLocalVariables;
@@ skipping 1030 matching lines @@
   void propertyNameOut(Expression node, {bool inMethod: false,
       bool inAccess: false}) {
 
     if (node is LiteralNumber) {
       LiteralNumber nameNumber = node;
       if (inAccess) out('[');
       out(nameNumber.value);
       if (inAccess) out(']');
     } else {
       if (node is LiteralString) {
-        var quotedName = node.value;
-        if (isValidJavaScriptId(quotedName)) {
+        if (isValidJavaScriptId(node.value)) {
           if (inAccess) out('.');
-          out(quotedName.substring(1, quotedName.length - 1));
+          out(node.valueWithoutQuotes);
         } else {
           if (inMethod || inAccess) out("[");
-          out(quotedName);
+          out(node.value);
           if (inMethod || inAccess) out("]");
         }
       } else {
         // ComputedPropertyName
         out("[");
         visitNestedExpression(node, EXPRESSION,
                               newInForInit: false, newAtStatementBegin: false);
         out("]");
       }
     }
@@ skipping 367 matching lines @@
     declare(node.name);
     node.function.accept(this);
   }
 
   visitClassExpression(ClassExpression node) {
     declare(node.name);
     if (node.heritage != null) node.heritage.accept(this);
     for (Method element in node.methods) element.accept(this);
   }
 }