format code, removed unused variables and deprecated usage

lib/src/option.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 args.src.option;
 
 import 'package:collection/wrappers.dart';
 
 /// Creates a new [Option].
 ///
@@ skipping 25 matching lines @@
   bool get isFlag => type == OptionType.FLAG;
 
   /// Whether the option takes a single value.
   bool get isSingle => type == OptionType.SINGLE;
 
   /// Whether the option allows multiple values.
   bool get isMultiple => type == OptionType.MULTIPLE;
 
   Option._(this.name, this.abbreviation, this.help, this.valueHelp,
       List<String> allowed, Map<String, String> allowedHelp, this.defaultValue,
-      this.callback, this.type, {this.negatable, this.hide: false}) :
-        this.allowed = allowed == null ?
-            null : new UnmodifiableListView(allowed),
-        this.allowedHelp = allowedHelp == null ?
-            null : new UnmodifiableMapView(allowedHelp) {
-
+      this.callback, this.type, {this.negatable, this.hide: false})
+      : this.allowed = allowed == null
+          ? null
+          : new UnmodifiableListView(allowed),
+        this.allowedHelp = allowedHelp == null
+            ? null
+            : new UnmodifiableMapView(allowedHelp) {
     if (name.isEmpty) {
       throw new ArgumentError('Name cannot be empty.');
     } else if (name.startsWith('-')) {
       throw new ArgumentError('Name $name cannot start with "-".');
     }
 
     // Ensure name does not contain any invalid characters.
     if (_invalidChars.hasMatch(name)) {
       throw new ArgumentError('Name "$name" contains invalid characters.');
     }
 
     if (abbreviation != null) {
       if (abbreviation.length != 1) {
         throw new ArgumentError('Abbreviation must be null or have length 1.');
-      } else if(abbreviation == '-') {
+      } else if (abbreviation == '-') {
         throw new ArgumentError('Abbreviation cannot be "-".');
       }
 
       if (_invalidChars.hasMatch(abbreviation)) {
         throw new ArgumentError('Abbreviation is an invalid character.');
       }
     }
   }
 
   /// Returns [value] if non-`null`, otherwise returns the default value for
@@ skipping 37 matching lines @@
   ///
   ///     --output text --output xml
   ///
   /// In the parsed [ArgResults], a multiple-valued option will always return
   /// a list, even if one or no values were passed.
   static const MULTIPLE = const OptionType._("OptionType.MULTIPLE");
 
   final String name;
 
   const OptionType._(this.name);
-}
+}