Get rid of all the library tags.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//1575233006 .
diff --git a/lib/args.dart b/lib/args.dart
index 562df44..2534082 100644
--- a/lib/args.dart
+++ b/lib/args.dart
@@ -2,8 +2,6 @@
 // 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 args;
-
 export 'src/arg_parser.dart';
 export 'src/arg_results.dart' hide newArgResults;
 export 'src/option.dart' hide newOption;
diff --git a/lib/command_runner.dart b/lib/command_runner.dart
index d728cb0..10b87ce 100644
--- a/lib/command_runner.dart
+++ b/lib/command_runner.dart
@@ -2,8 +2,6 @@
 // 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 args.command_runner;
-
 import 'dart:async';
 import 'dart:collection';
 import 'dart:math' as math;
diff --git a/lib/src/arg_parser.dart b/lib/src/arg_parser.dart
index c32741d..0b81fed 100644
--- a/lib/src/arg_parser.dart
+++ b/lib/src/arg_parser.dart
@@ -2,8 +2,6 @@
 // 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 args.src.arg_parser;
-
 import 'dart:collection';
 
 import 'arg_results.dart';
diff --git a/lib/src/arg_results.dart b/lib/src/arg_results.dart
index 6be2de4..50e85fa 100644
--- a/lib/src/arg_results.dart
+++ b/lib/src/arg_results.dart
@@ -2,8 +2,6 @@
 // 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 args.src.arg_results;
-
 import 'dart:collection';
 
 import 'arg_parser.dart';
diff --git a/lib/src/help_command.dart b/lib/src/help_command.dart
index f477b47..9ffcbe1 100644
--- a/lib/src/help_command.dart
+++ b/lib/src/help_command.dart
@@ -2,8 +2,6 @@
 // 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 args.help_command;
-
 import '../command_runner.dart';
 
 /// The built-in help command that's added to every [CommandRunner].
diff --git a/lib/src/option.dart b/lib/src/option.dart
index 07e87f6..a37193f 100644
--- a/lib/src/option.dart
+++ b/lib/src/option.dart
@@ -2,8 +2,6 @@
 // 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 args.src.option;
-
 import 'dart:collection';
 
 /// Creates a new [Option].
diff --git a/lib/src/parser.dart b/lib/src/parser.dart
index a10692d..c36035c 100644
--- a/lib/src/parser.dart
+++ b/lib/src/parser.dart
@@ -2,8 +2,6 @@
 // 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 args.src.parser;
-
 import 'arg_parser.dart';
 import 'arg_results.dart';
 import 'option.dart';
diff --git a/lib/src/usage.dart b/lib/src/usage.dart
index 177a810..2b40332 100644
--- a/lib/src/usage.dart
+++ b/lib/src/usage.dart
@@ -2,8 +2,6 @@
 // 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 args.src.usage;
-
 import 'dart:math';
 
 import '../args.dart';
diff --git a/lib/src/usage_exception.dart b/lib/src/usage_exception.dart
index 35cc744..2d8e112 100644
--- a/lib/src/usage_exception.dart
+++ b/lib/src/usage_exception.dart
@@ -2,8 +2,6 @@
 // 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 args.usage_exception;
-
 class UsageException implements Exception {
   final String message;
   final String usage;
diff --git a/lib/src/utils.dart b/lib/src/utils.dart
index dc355df..2469fac 100644
--- a/lib/src/utils.dart
+++ b/lib/src/utils.dart
@@ -2,8 +2,6 @@
 // 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 args.utils;
-
 /// Pads [source] to [length] by adding spaces at the end.
 String padRight(String source, int length) =>
     source + ' ' * (length - source.length);
diff --git a/test/args_test.dart b/test/args_test.dart
index ee37b45..4553b30 100644
--- a/test/args_test.dart
+++ b/test/args_test.dart
@@ -2,8 +2,6 @@
 // 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 args_test;
-
 import 'package:test/test.dart';
 import 'package:args/args.dart';
 import 'utils.dart';
diff --git a/test/command_parse_test.dart b/test/command_parse_test.dart
index 54b3032..269ed01 100644
--- a/test/command_parse_test.dart
+++ b/test/command_parse_test.dart
@@ -2,8 +2,6 @@
 // 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 command_parse_test;
-
 import 'package:test/test.dart';
 import 'package:args/args.dart';
 import 'utils.dart';
diff --git a/test/command_runner_test.dart b/test/command_runner_test.dart
index 3a796f1..f3a74a0 100644
--- a/test/command_runner_test.dart
+++ b/test/command_runner_test.dart
@@ -2,8 +2,6 @@
 // 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 command_runner_test;
-
 import 'package:args/command_runner.dart';
 import 'package:test/test.dart';
 
diff --git a/test/command_test.dart b/test/command_test.dart
index 888016a..127cfc9 100644
--- a/test/command_test.dart
+++ b/test/command_test.dart
@@ -2,8 +2,6 @@
 // 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 command_test;
-
 import 'package:args/command_runner.dart';
 import 'package:test/test.dart';
 import 'utils.dart';
diff --git a/test/parse_test.dart b/test/parse_test.dart
index 39027c2..187f735 100644
--- a/test/parse_test.dart
+++ b/test/parse_test.dart
@@ -2,8 +2,6 @@
 // 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 parse_test;
-
 import 'package:test/test.dart';
 import 'package:args/args.dart';
 import 'utils.dart';
diff --git a/test/trailing_options_test.dart b/test/trailing_options_test.dart
index efc53b2..cdc4227 100644
--- a/test/trailing_options_test.dart
+++ b/test/trailing_options_test.dart
@@ -2,8 +2,6 @@
 // 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 trailing_options_test;
-
 import 'package:test/test.dart';
 import 'package:args/args.dart';
 
diff --git a/test/usage_test.dart b/test/usage_test.dart
index 492c517..31c19d2 100644
--- a/test/usage_test.dart
+++ b/test/usage_test.dart
@@ -2,8 +2,6 @@
 // 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 usage_test;
-
 import 'package:test/test.dart';
 import 'package:args/args.dart';
 
diff --git a/test/utils.dart b/test/utils.dart
index 1cdd803..b6c6c71 100644
--- a/test/utils.dart
+++ b/test/utils.dart
@@ -2,8 +2,6 @@
 // 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 utils;
-
 import 'dart:async';
 
 import 'package:args/args.dart';