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

tests/html/indexeddb_3_test.dart

-#library('IndexedDB3Test');
-#import('../../pkg/unittest/unittest.dart');
-#import('../../pkg/unittest/html_config.dart');
-#import('dart:html');
+library IndexedDB3Test;
+import '../../pkg/unittest/lib/unittest.dart';
+import '../../pkg/unittest/lib/html_config.dart';
+import 'dart:html';
 
 // Read with cursor.
 
 const String DB_NAME = 'Test';
 const String STORE_NAME = 'TEST';
 const int VERSION = 1;
 
 class Test {
   fail(message) => (e) {
     guardAsync(() {
@@ skipping 125 matching lines @@
 }
 
 main() {
   useHtmlConfiguration();
 
   var test_ = new Test();
   test('prepare', test_.setupDb);
   test('readAll1', test_.readAllViaCursor);
   test('readAll2', test_.readAllReversedViaCursor);
 }