Update charted to 0.4.8 and roll

packages/charted/test.disabled/charts/transformers/aggregation_transformer_test.dart

 /*
  * Copyright 2014 Google Inc. All rights reserved.
  *
  * Use of this source code is governed by a BSD-style
  * license that can be found in the LICENSE file or at
  * https://developers.google.com/open-source/licenses/bsd
  */
 library charted.test.aggregationtransformer;
 
 import 'package:charted/charts/charts.dart';
 import 'package:charted/core/utils.dart';
 import 'package:unittest/unittest.dart';
-import 'package:observe/observe.dart';
+import 'package:observable/observable.dart';
 
 main() {
   List COLUMNS = [
       new ChartColumnSpec(label:'Continent', type:ChartColumnSpec.TYPE_STRING),
       new ChartColumnSpec(label:'Country', type:ChartColumnSpec.TYPE_STRING),
       new ChartColumnSpec(label:'City', type:ChartColumnSpec.TYPE_STRING),
       new ChartColumnSpec(label:'Stats1'),
       new ChartColumnSpec(label:'Stats2'),
       new ChartColumnSpec(label:'Stats3')
     ];
@@ skipping 348 matching lines @@
     (observableData as Observable).deliverChanges();
 
     // [Argentina, , , 2000.0, 5.50]
     // [Brazil, , , 6000.0, 2.50]
     expect(result.rows.elementAt(0).elementAt(3), equals(2000));
     expect(result.rows.elementAt(0).elementAt(4), closeTo(5.5, EPSILON));
     expect(result.rows.elementAt(1).elementAt(3), equals(6000));
     expect(result.rows.elementAt(1).elementAt(4), closeTo(1.5, EPSILON));
   });
 }