Get rid of all the library tags.

lib/src/asset/dart/serialize/transformer.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 pub.asset.serialize.transformer;
-
 import 'dart:async';
 import 'dart:isolate';
 
 import 'package:barback/barback.dart';
 
 import '../serialize.dart';
 import 'transform.dart';
 
 /// Converts [transformer] into a serializable map.
 Map _serializeTransformer(Transformer transformer) {
@@ skipping 100 matching lines @@
     return _serializeTransformer(transformerLike);
   } else if (transformerLike is TransformerGroup) {
     return _serializeTransformerGroup(transformerLike);
   } else {
     // This has to be last, since "transformerLike is AggregateTransformer" will
     // throw on older versions of barback.
     assert(transformerLike is AggregateTransformer);
     return _serializeAggregateTransformer(transformerLike);
   }
 }