Fix type error, add tests for it, get package ready for a patch release.

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.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';
 
 
 /** Collects different parameters needed to configure and run barback. */
 class BarbackOptions {
   /** Phases of transformers to run. */
   final List<List<Transformer>> phases;
@@ skipping 13 matching lines @@
   /** Whether to apply transformers on polymer dependencies. */
   final bool transformPolymerDependencies;
 
   /** Directory where to generate code, if any. */
   final String outDir;
 
   /**
    * Whether to print error messages using a json-format that tools, such as the
    * Dart Editor, can process.
    */
-  final String machineFormat;
+  final bool machineFormat;
 
   BarbackOptions(this.phases, this.outDir, {currentPackage, packageDirs,
       this.transformTests: false, this.transformPolymerDependencies: false,
       this.machineFormat: false})
       : currentPackage = (currentPackage != null
           ? currentPackage : readCurrentPackageFromPubspec()),
         packageDirs = (packageDirs != null
           ? packageDirs : _readPackageDirsFromPub(currentPackage));
 
 }
@@ skipping 310 matching lines @@
     output.write(entry.span.getLocationMessage(entry.message,
           useColors: useColors,
           color: levelColor));
   }
   return output.toString();
 }
 
 const String _RED_COLOR = '\u001b[31m';
 const String _MAGENTA_COLOR = '\u001b[35m';
 const String _NO_COLOR = '\u001b[0m';