Get rid of all the library tags.

lib/src/yaml_node_wrapper.dart

 // Copyright (c) 2014, 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 yaml.yaml_node_wrapper;
-
 import 'dart:collection';
 
 import 'package:collection/collection.dart' as pkg_collection;
 import 'package:source_span/source_span.dart';
 
 import 'null_span.dart';
 import 'style.dart';
 import 'yaml_node.dart';
 
 /// A wrapper that makes a normal Dart map behave like a [YamlMap].
@@ skipping 129 matching lines @@
 
   operator ==(Object other) =>
       other is _YamlListNodes && other._dartList == _dartList;
 }
 
 YamlNode _nodeForValue(value, SourceSpan span) {
   if (value is Map) return new YamlMapWrapper._(value, span);
   if (value is List) return new YamlListWrapper._(value, span);
   return new YamlScalar.internalWithSpan(value, span);
 }