Update charted to 0.4.8 and roll

packages/charted/lib/core/utils/lists.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
 //
 
 part of charted.core.utils;
 
 /// Returns a sum of all values in the given list of values
 num sum(List values) => values == null || values.isEmpty
     ? 0
     : values.fold(0.0, (old, next) => old + next);
 
 /// Returns the smallest number in the given list of values
-num min(Iterable values) => values == null || values.isEmpty
+num min(Iterable<num> values) => values == null || values.isEmpty
     ? null
-    : values.fold(values.elementAt(0), math.min);
+    : values.fold(values.elementAt(0), (x, y) => math.min(x, y));
 
 /// Returns the largest number in the given list of values
-num max(Iterable values) => values == null || values.isEmpty
+num max(Iterable<num> values) => values == null || values.isEmpty
     ? null
-    : values.fold(values.elementAt(0), math.max);
+    : values.fold(values.elementAt(0), (x, y) => math.max(x, y));
 
 /// Represents a constant pair of values
 class Pair<T1, T2> {
   final T1 first;
   final T2 last;
 
   const Pair(this.first, this.last);
 
   bool operator ==(other) =>
       other is Pair && first == other.first && last == other.last;
@@ skipping 68 matching lines @@
       : super(values);
 
   static int _integerConversionFactor(num val) {
     int k = 1;
     while (val * k % 1 > 0) {
       k *= 10;
     }
     return k;
   }
 }