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

pkg/unittest/test/instance_test.dart

Index: pkg/unittest/test/instance_test.dart
===================================================================
--- pkg/unittest/test/instance_test.dart	(revision 14313)
+++ pkg/unittest/test/instance_test.dart	(working copy)
@@ -2,10 +2,11 @@
 // 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('instance_test');
-#import('../../../pkg/unittest/unittest.dart');
-#source('test_utils.dart');
+library instance_test;
+import '../../../pkg/unittest/lib/unittest.dart';
 
+part 'test_utils.dart';
+
 doesThrow() { throw 'X'; }
 
 main() {