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

lib/unittest/core_matchers.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.
 
 
 /**
  * Returns a matcher that matches empty strings, maps or collections.
  */
 final Matcher isEmpty = const _Empty();
 
@@ skipping 197 matching lines @@
  *
  * For example, to test whether 'bar' is an instance of type
  * 'Foo', we would write:
  *
  *     expect(bar, new isInstanceOf<Foo>());
  *
  * To get better error message, supply a name when creating the
  * Type wrapper; e.g.:
  *
  *     expect(bar, new isInstanceOf<Foo>('Foo'));
+ *
+ * Note that this does not currently work in dart2js; it will 
+ * match any type, and isNot(new isInstanceof<T>()) will always
+ * fail. This is because dart2js currently ignores template type
+ * parameters.
  */
 class isInstanceOf<T> extends BaseMatcher {
   final String _name;
   const isInstanceOf([name = 'specified type']) : this._name = name;
   bool matches(obj, MatchState matchState) => obj is T;
   // The description here is lame :-(
   Description describe(Description description) =>
       description.add('an instance of ${_name}');
 }
 
@@ skipping 389 matching lines @@
   final _matcher;
   final String _description;
 
   const _Predicate(this._matcher, this._description);
 
   bool matches(item, MatchState matchState) => _matcher(item);
 
   Description describe(Description description) =>
       description.add(_description);
 }