Move Arrays, Collections and Maps into a new library, dart:collections.

lib/collection/collection.dart

Index: lib/collection/collection.dart
diff --git a/lib/html/templates/html/impl/factoryprovider_Elements.darttemplate b/lib/collection/collection.dart
similarity index 72%
copy from lib/html/templates/html/impl/factoryprovider_Elements.darttemplate
copy to lib/collection/collection.dart
index 561ece0d5cce9beb76d264ce5b0654a9076aeda0..8c735395798e787ad64a852b4d48c759b68267f3 100644
--- a/lib/html/templates/html/impl/factoryprovider_Elements.darttemplate
+++ b/lib/collection/collection.dart
@@ -2,8 +2,8 @@
 // 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 html;
+library collection;
 
-class _Elements {
-
-$!FACTORY_METHODS}
+part 'arrays.dart';
+part 'collections.dart';
+part 'maps.dart';