Update charted to 0.4.8 and roll

packages/charted/examples/charts/demo_interactive.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.demo.interactive;
 
 import 'dart:html';
-import 'package:observe/observe.dart';
+import 'package:observable/observable.dart';
 import 'package:charted/charts/charts.dart';
 
 import 'demo_charts.dart';
 
 const List<int> DIMENSION_COLUMNS =  const <int>[0, 4];
 
 int customSeriesCounter = 0;
 
 Map RENDERERS = {
   'bar-chart': 'Bar chart',
   'line-chart': 'Line chart',
   'stacked-bar-chart': 'Stacked bar chart',
+  'stacked-line-chart': 'Stacked line chart',
   'waterfall-chart': 'Waterfall chart',
 };
 
 CartesianRenderer getRendererForType(String name) {
   if (name == 'bar-chart') return new BarChartRenderer();
   if (name == 'line-chart') return new LineChartRenderer();
   if (name == 'stacked-bar-chart') return new StackedBarChartRenderer();
+  if (name == 'stacked-line-chart') return new StackedLineChartRenderer();
   return new BarChartRenderer();
 }
 
 String getTypeForRenderer(CartesianRenderer renderer) {
   if (renderer is BarChartRenderer) return 'bar-chart';
   if (renderer is LineChartRenderer) return 'line-chart';
   if (renderer is StackedBarChartRenderer) return 'stacked-bar-chart';
+  if (renderer is StackedLineChartRenderer) return 'stacked-line-chart';
   return 'bar-chart';
 }
 
 main() {
   List<List> DATA_SOURCE = ORDINAL_DATA;
   ChartSeries activeSeries,
       defaultSeries = new ChartSeries("Default series",
           new ObservableList.from([ 2, 3 ]), new BarChartRenderer());
 
   var rows = new ObservableList<List>.from(DATA_SOURCE.sublist(0, 10));
@@ skipping 199 matching lines @@
 
 
   /*
    * Update UI
    */
 
   updateColumnsList();
   updateRendererSelector();
   updateSeriesSelector();
 }