Remove dart:json

BUG= http://dartbug.com/12843
R=floitsch@google.com, fschneider@google.com

Review URL: https://codereview.chromium.org//40323002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/yaml@29240 260f80e4-7a28-3924-810f-c04153c831b5
diff --git a/README.md b/README.md
index ad7678f..47a5419 100644
--- a/README.md
+++ b/README.md
@@ -10,13 +10,13 @@
     }
 
 This library currently doesn't support dumping to YAML. You should use
-`stringify` from `dart:json` instead:
+`JSON.encode` from `dart:convert` instead:
 
-    import 'dart:json' as json;
+    import 'dart:convert';
     import 'package:yaml/yaml.dart';
     main() {
       var doc = loadYaml("YAML: YAML Ain't Markup Language");
-      print(json.stringify(doc));
+      print(JSON.encode(doc));
     }
 
 The source code for this package is at <http://code.google.com/p/dart>.