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

tests/html/element_add_test.dart

 // Copyright (c) 2012, 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('ElementAddTest');
-#import('../../pkg/unittest/unittest.dart');
-#import('../../pkg/unittest/html_config.dart');
-#import('dart:html');
-#source('util.dart');
+library ElementAddTest;
+import '../../pkg/unittest/lib/unittest.dart';
+import '../../pkg/unittest/lib/html_config.dart';
+import 'dart:html';
+part 'util.dart';
 
 main() {
   useHtmlConfiguration();
 
   var isSpanElement = predicate((x) => x is SpanElement, 'is a SpanElemt');
   var isDivElement = predicate((x) => x is DivElement, 'is a DivElement');
   var isText = predicate((x) => x is Text, 'is a Text');
 
   void expectNoSuchMethod(void fn()) =>
     expect(fn, throwsNoSuchMethodError);
@@ skipping 176 matching lines @@
       var child = new DivElement();
       parent.elements.add(child);
 
       parent.insertAdjacentText('beforeend', 'test');
 
       expect(parent.nodes.length, 2);
       expect(parent.nodes[1], isText);
     });
   });
 }