Move assets into lib/src.

lib/src/barback/transformer_isolate.dart

 // Copyright (c) 2013, 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.transformer_isolate;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:isolate';
 
 import 'package:barback/barback.dart';
 import 'package:source_span/source_span.dart';
 import 'package:stack_trace/stack_trace.dart';
 
-import '../../../asset/dart/serialize.dart';
+import '../asset/dart/serialize.dart';
 import '../barback.dart';
 import '../exceptions.dart';
 import '../dart.dart' as dart;
 import '../log.dart' as log;
 import '../utils.dart';
 import 'asset_environment.dart';
 import 'barback_server.dart';
 import 'foreign_transformer.dart';
 import 'transformer_config.dart';
 import 'transformer_id.dart';
@@ skipping 109 matching lines @@
 /// An error thrown when a transformer fails to load.
 class TransformerLoadError extends SourceSpanException
     implements WrappedException {
   final CrossIsolateException innerError;
   Chain get innerChain => innerError.stackTrace;
 
   TransformerLoadError(CrossIsolateException error, SourceSpan span)
       : innerError = error,
         super("Error loading transformer: ${error.message}", span);
 }