Get rid of all the library tags.

lib/src/command_runner.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.command_runner;
-
 import 'dart:async';
 import 'dart:io';
 
 import 'package:args/args.dart';
 import 'package:args/command_runner.dart';
 import 'package:http/http.dart' as http;
 import 'package:path/path.dart' as p;
 
 import 'command/build.dart';
 import 'command/cache.dart';
@@ skipping 198 matching lines @@
   Future _validatePlatform() async {
     if (Platform.operatingSystem != 'windows') return;
 
     var result = await runProcess('ver', []);
     if (result.stdout.join('\n').contains('XP')) {
       log.error('Sorry, but pub is not supported on Windows XP.');
       await flushThenExit(exit_codes.USAGE);
     }
   }
 }