Get rid of all the library tags.

lib/src/exceptions.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.exceptions;
-
 import 'dart:io';
 import 'dart:isolate';
 
 import "package:analyzer/analyzer.dart";
 import 'package:args/command_runner.dart';
 import "package:http/http.dart" as http;
 import "package:stack_trace/stack_trace.dart";
 import "package:yaml/yaml.dart";
 
 import 'asset/dart/serialize.dart';
@@ skipping 93 matching lines @@
   // fixed.
   return error is ApplicationException ||
     error is AnalyzerError ||
     error is AnalyzerErrorGroup ||
     error is IsolateSpawnException ||
     error is IOException ||
     error is http.ClientException ||
     error is YamlException ||
     error is UsageException;
 }