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

tests/html/node_test.dart

 // 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('NodeTest');
-#import('../../pkg/unittest/unittest.dart');
-#import('../../pkg/unittest/html_config.dart');
-#import('dart:html');
+library NodeTest;
+import '../../pkg/unittest/lib/unittest.dart';
+import '../../pkg/unittest/lib/html_config.dart';
+import 'dart:html';
 
 Node makeNode() => new Element.tag('div');
 Node makeNodeWithChildren() =>
   new Element.html("<div>Foo<br/><!--baz--></div>");
 
 main() {
   useHtmlConfiguration();
 
   var isText = predicate((x) => x is Text, 'is a Text');
   var isComment = predicate((x) => x is Comment, 'is a Comment');
@@ skipping 178 matching lines @@
     });
 
     test('getRange', () {
       var range = makeNodeList().getRange(1, 2);
       expect(range, isNodeList);
       expect(range[0], isBRElement);
       expect(range[1], isComment);
     });
   });
 }