Update charted to 0.4.8 and roll

packages/observable/lib/observable.dart

Index: packages/observable/lib/observable.dart
diff --git a/packages/observable/lib/observable.dart b/packages/observable/lib/observable.dart
new file mode 100644
index 0000000000000000000000000000000000000000..ce8206185e04a6e1c27ab0352ea3ba7aa4f725ca
--- /dev/null
+++ b/packages/observable/lib/observable.dart
@@ -0,0 +1,13 @@
+// Copyright (c) 2016, 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.
+
+library observable;
+
+export 'src/change_record.dart';
+export 'src/list_diff.dart' show ListChangeRecord;
+export 'src/observable.dart';
+export 'src/observable_list.dart';
+export 'src/observable_map.dart';
+export 'src/property_change_record.dart';
+export 'src/to_observable.dart';