Update charted to 0.4.8 and roll

packages/petitparser/lib/json.dart

-/// This package contains a complete implementation of [JSON](http://json.org/).
-///
-/// [JsonParser] creates a nested Dart objects from a given JSON string. For
-/// example the following code prints `{a: 1, b: [2, 3.4], c: false}`:
-///
-///     var json = new JsonParser();
-///     var result = json.parse('{"a": 1, "b": [2, 3.4], "c": false}');
-///     print(result.value);  // {a: 1, b: [2, 3.4], c: false}
-///
-/// The grammar definition [JsonGrammar] can be subclassed to construct other
-/// objects.
-library petitparser.json;
-
-import 'dart:collection';
-import 'petitparser.dart';
-
-part 'src/json/grammar.dart';
-part 'src/json/parser.dart';