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

pkg/intl/test/bidi_format_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 bidi_format_test;
 
 import '../lib/intl.dart';
-import '../../../pkg/unittest/unittest.dart';
+import '../../../pkg/unittest/lib/unittest.dart';
 
 /**
  * Tests the bidirectional text formatting library.
  */
 main() {
   var LTR = TextDirection.LTR;
   var RTL = TextDirection.RTL;
   var LRM = Bidi.LRM;
   var RLM = Bidi.RLM;
   var RLE = Bidi.RLE;
@@ skipping 198 matching lines @@
     expect(rtlFmt.wrapWithUnicode(he, direction : TextDirection.LTR),
         equals('$LRE$he$PDF$RLM'));
     // Test supposed overall dir (LTR) doesn't match context dir (unknown).
     expect(unkFmt.wrapWithUnicode(he, direction : TextDirection.LTR),
         equals('$LRE$he$PDF'));
     // Test supposed overall dir (neutral) doesn't match context dir (LTR).
     expect(ltrFmt.wrapWithUnicode(he, direction : TextDirection.UNKNOWN),
         equals('$he$LRM'));
   });
 }