Update charted to 0.4.8 and roll

packages/charted/lib/core/scales.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
 //
 
 /// Collection of scales for use by charts. The role of scales is to map the
 /// input domain to an output range.
@@ skipping 47 matching lines @@
   /// For ordinal scale, the returned function is an identity function.
   FormatFunction createTickFormatter([String format]);
 
   /// Creates a clone of this scale.
   Scale clone();
 
   /// Suggested number of ticks on this scale.
   /// Note: This property is only valid on quantitative scales.
   int ticksCount;
 
+  /// Forces the number of ticks on this scale to be the forcedTicksCount.
+  /// The tick values on the scale does not guarantee to be niced numbers, but
+  /// domain of the scale does.
+  /// Note: This property is only valid on quantitative scales.
+  int forcedTicksCount;
+
   /// Indicates if the current scale is using niced values for ticks.
   /// Note: This property is only valid on quantitative scales.
   bool nice;
 
   /// Indicates if output range is clamped.  When clamp is not true, any input
   /// value that is not within the input domain may result in a value that is
   /// outside the output range.
   /// Note: This property is only valid on quantitative scales.
   bool clamp;
 
@@ skipping 144 matching lines @@
         hi = mid;
       } else {
         lo = mid + 1;
       }
     }
     return lo;
   }
 
   static Function bisect = bisectRight;
 }