Modernize the package's style.

lib/collection.dart

 // Copyright (c) 2013, 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.
 
-/**
- * Exports all the individual parts of the collection-helper library.
- *
- * The sub-libraries of this package are:
- *
- * - `algorithms.dart`: Algorithms that work on lists (shuffle, binary search
- *                      and various sorting algorithms).
- * - `equality.dart`: Different notions of equality of collections.
- * - `iterable_zip.dart`: Combining multiple iterables into one.
- * - `priority_queue.dart`: Priority queue type and implementations.
- * - `wrappers.dart`: Wrapper classes that delegate to a collection object.
- *                    Includes unmodifiable views of collections.
- */
-library dart.pkg.collection;
-
-export "algorithms.dart";
-export "equality.dart";
-export "iterable_zip.dart";
-export "priority_queue.dart";
+export "src/algorithms.dart";
 export "src/canonicalized_map.dart";
 export "src/comparators.dart";
+export "src/equality.dart";
+export "src/iterable_zip.dart";
+export "src/priority_queue.dart";
 export "src/queue_list.dart";
-export "wrappers.dart";
+export "src/unmodifiable_wrappers.dart";
+export "src/wrappers.dart";