Make getKeys, getValues getters (keys, values).

pkg/intl/test/number_format_test.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.
  */
 
 #library('number_format_test');
 
 #import('../../../pkg/unittest/unittest.dart');
 #import('../lib/number_format.dart');
@@ skipping 23 matching lines @@
   "-∞": -1/0};
 
 main() {
   test('Basic number printing', () {
     var number = new NumberFormat();
     expect(number.format(3.14),"3.14");
   });
 
   test('Simple set of numbers', () {
     var number = new NumberFormat();
-    for (var x in testNumbers.getKeys()) {
+    for (var x in testNumbers.keys) {
       var formatted = number.format(testNumbers[x]);
       expect(formatted, x);
     }
   });
 }