Rearranges the polymer package now that the old compiler is gone.

pkg/polymer/lib/src/build/runner.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.
 
 /**
  * Definitions used to run the polymer linter and deploy tools without using
  * pub serve or pub deploy.
  */
-library polymer.src.barback_runner;
+library polymer.src.build.runner;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
 import 'package:args/args.dart';
 import 'package:barback/barback.dart';
 import 'package:path/path.dart' as path;
 import 'package:stack_trace/stack_trace.dart';
 import 'package:yaml/yaml.dart';
@@ skipping 283 matching lines @@
   return writer.addStream(new File(inpath).openRead())
       .then((_) => writer.close());
 }
 
 /** Write contents of an [asset] into a file at [filepath]. */
 Future _writeAsset(String filepath, Asset asset) {
   _ensureDir(path.dirname(filepath));
   var writer = new File(filepath).openWrite();
   return writer.addStream(asset.read()).then((_) => writer.close());
 }