Move some core classes to collection library.

sdk/lib/collection/queue.dart

 // Copyright (c) 2011, 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.
 
-part of dart.core;
+part of dart.collection;
 
 /**
  * A [Queue] is a collection that can be manipulated at both ends. One
  * can iterate over the elements of a queue through [forEach] or with
  * an [Iterator].
  */
 abstract class Queue<E> extends Collection<E> {
 
   /**
    * Creates a queue.
@@ skipping 294 matching lines @@
       _current = null;
       _sentinel = null;
       return false;
     }
     _current = _currentEntry.element;
     return true;
   }
 
   E get current => _current;
 }