Revert "Switch libraries to using new tags."

sdk/lib/core/iterable.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;
-
 /**
  * The [Iterable] interface allows to get an [Iterator] out of an
  * [Iterable] object.
  *
  * This interface is used by the for-in construct to iterate over an
  * [Iterable] object.
  * The for-in construct takes an [Iterable] object at the right-hand
  * side, and calls its [iterator] method to get an [Iterator] on it.
  *
  * A user-defined class that implements the [Iterable] interface can
  * be used as the right-hand side of a for-in construct.
  */
 abstract class Iterable<E> {
   /**
    * Returns an [Iterator] that iterates over this [Iterable] object.
    */
   Iterator<E> iterator();
 }