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

pkg/intl/test/date_time_format_file_test_stub.dart

Index: pkg/intl/test/date_time_format_file_test_stub.dart
===================================================================
--- pkg/intl/test/date_time_format_file_test_stub.dart	(revision 14440)
+++ pkg/intl/test/date_time_format_file_test_stub.dart	(working copy)
@@ -14,7 +14,7 @@
 import 'dart:io';
 import 'date_time_format_test_core.dart';
 import 'data_directory.dart';
-import '../../../pkg/unittest/unittest.dart';
+import '../../../pkg/unittest/lib/unittest.dart';
 
 runWith([Function getSubset]) {
   // Initialize one locale just so we know what the list is.
@@ -32,4 +32,4 @@
     Futures.wait(futures).then(
         expectAsync1((results) => runDateTests(getSubset())));
   });
-}
+}