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

tests/isolate/timer_cancel_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('timer_cancel_test');
+library timer_cancel_test;
 
-#import("dart:isolate");
-#import('../../pkg/unittest/unittest.dart');
+import 'dart:isolate';
+import '../../pkg/unittest/lib/unittest.dart';
 
 main() {
   test("simple timer", () {
     Timer cancelTimer;
     int repeatTimer;
 
     void unreachable(Timer timer) {
       fail("should not be reached");
     }
 
@@ skipping 14 matching lines @@
     repeatTimer = 0;
     new Timer.repeating(1500, expectAsync1(repeatHandler));
   });
   
   test("cancel timer with same time", () {
     var t2;
     var t1 = new Timer(0, expectAsync1((t) => t2.cancel()));
     t2 = new Timer(0, expectAsync1((t) => t1.cancel(), count: 0));
   });
 }