yaml: reformat, fix README and homepage link, bump version

README.md

 A parser for [YAML](http://www.yaml.org/).
 
 Use `loadYaml` to load a single document, or `loadYamlStream` to load a
 stream of documents. For example:
 
 ```dart
 import 'package:yaml/yaml.dart';
 
 main() {
   var doc = loadYaml("YAML: YAML Ain't Markup Language");
   print(doc['YAML']);
 }
 ```
 
 This library currently doesn't support dumping to YAML. You should use
 `JSON.encode` from `dart:convert` instead:
 
 ```dart
 import 'dart:convert';
 import 'package:yaml/yaml.dart';
 
 main() {
   var doc = loadYaml("YAML: YAML Ain't Markup Language");
   print(JSON.encode(doc));
 }
 ```
-
-The source code for this package is at <http://code.google.com/p/dart>.
-Please file issues at <http://dartbug.com>. Other questions or comments can be
-directed to the Dart mailing list at <mailto:misc@dartlang.org>.