Remove uses of Options from pkg, samples, tests, and third_party directories.

pkg/args/lib/args.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.
 
 /**
  * Parser support for transforming raw command-line arguments into a set
  * of options and values.
  *
  * This library supports [GNU][] and [POSIX][] style options, and it works
  * in both server-side and client-side apps.
@@ skipping 66 matching lines @@
  * is parsed. If an option isn't provided in the args, its callback is
  * passed the default value, or `null` if no default value is set.
  *
  * ## Parsing arguments
  *
  * Once you have an [ArgParser] set up with some options and flags, you
  * use it by calling [ArgParser.parse()] with a set of arguments:
  *
  *     var results = parser.parse(['some', 'command', 'line', 'args']);
  *
- * These arguments usually come from dart:io's Options class
- * (`new Options().arguments`), but you can pass in any list of strings.
+ * These arguments usually come from the arguments to main
+ * (`main(List<String> arguments`), but you can pass in any list of strings.
  * The parse() method returns an instance of [ArgResults], a map-like
  * object that contains the values of the parsed options.
  *
  *     var parser = new ArgParser();
  *     parser.addOption('mode');
  *     parser.addFlag('verbose', defaultsTo: true);
  *     var results = parser.parse(['--mode', 'debug', 'something', 'else']);
  *
  *     print(results['mode']); // debug
  *     print(results['verbose']); // true
@@ skipping 347 matching lines @@
           'Could not find an option named "$name".');
     }
 
     return _options[name];
   }
 
   /** Get the names of the options as an [Iterable]. */
   Iterable<String> get options => _options.keys;
 }