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

pkg/args/lib/args.dart

Index: pkg/args/lib/args.dart
diff --git a/pkg/args/lib/args.dart b/pkg/args/lib/args.dart
index a4db2046347bd6963cb12160d8dec1e79f286ba4..ea7f2318aa54a41873241e6c3b9aa3b6966fa877 100644
--- a/pkg/args/lib/args.dart
+++ b/pkg/args/lib/args.dart
@@ -84,8 +84,8 @@
  *
  *     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.
  *