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

tests/html/table_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('TableTest');
-#import('../../pkg/unittest/unittest.dart');
-#import('../../pkg/unittest/html_config.dart');
-#import('dart:html');
+library TableTest;
+import '../../pkg/unittest/lib/unittest.dart';
+import '../../pkg/unittest/lib/html_config.dart';
+import 'dart:html';
 
 main() {
   useHtmlConfiguration();
 
   test('createTBody', () {
     var table = new TableElement();
     var head = table.createTHead();
     var headerRow =  head.insertRow(-1);
     var headerCell = headerRow.insertCell(-1);
     headerCell.text = 'Header Cell';
@@ skipping 15 matching lines @@
     var bodyRow2 =  body2.insertRow(-1);
     var bodyCell2 = bodyRow2.insertCell(-1);
     bodyCell2.text = 'Body Cell2';
 
     expect(table.tBodies.length, 2);
     expect(table.tBodies[1], body2);
 
   });
 }