Restructure pkg/unittest and pkg/webdriver to follow the pub conventions.

pkg/webdriver/lib/webdriver.dart

-#library('webdriver');
+// Copyright (c) 2011, 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 webdriver;
+
 #import('dart:json');
 #import('dart:uri');
 #import('dart:io');
 #import('dart:math');
-#source('base64decoder.dart');
+
+part 'src/base64decoder.dart';
 
 /**
  * WebDriver bindings for Dart.
  *
  * These bindings are based on the WebDriver JSON wire protocol spec
  * (http://code.google.com/p/selenium/wiki/JsonWireProtocol). Not
  * all of these commands are implemented yet by WebDriver itself.
  * Nontheless this is a complete implementation of the spec as the
  * unsupported commands may be supported in the future. Currently,
  * there are known issues with local and session storage, script
@@ skipping 1334 matching lines @@
    * Get the log for a given log type. Log buffer is reset after each request.
    * Each log entry is a [Map] with these fields:
    *
    * 'timestamp' (int) - The timestamp of the entry.
    * 'level' (String) - The log level of the entry, for example, "INFO".
    * 'message' (String) - The log message.
    */
   Future<List<Map>> getLogs(String type) =>
       _post('log', params: { 'type': type });
 }