Update charted to 0.4.8 and roll

packages/observe/README.md

-# observe
-
-Support for marking objects as observable, and getting notifications when those
-objects are mutated.
-
-**Warning:** This library is experimental, and APIs are subject to change.
-
-This library is used to observe changes to [Observable][] types. It also
-has helpers to make implementing and using [Observable][] objects easy.
-
-You can provide an observable object in two ways. The simplest way is to
-use dirty checking to discover changes automatically:
-
-```dart
-import 'package:observe/observe.dart';
-import 'package:observe/mirrors_used.dart'; // for smaller code
-
-class Monster extends Unit with Observable {
-  @observable int health = 100;
-
-  void damage(int amount) {
-    print('$this takes $amount damage!');
-    health -= amount;
-  }
-
-  toString() => 'Monster with $health hit points';
-}
-
-main() {
-  var obj = new Monster();
-  obj.changes.listen((records) {
-    print('Changes to $obj were: $records');
-  });
-  // No changes are delivered until we check for them
-  obj.damage(10);
-  obj.damage(20);
-  print('dirty checking!');
-  Observable.dirtyCheck();
-  print('done!');
-}
-```
-
-A more sophisticated approach is to implement the change notification
-manually. This avoids the potentially expensive [Observable.dirtyCheck][]
-operation, but requires more work in the object:
-
-```dart
-import 'package:observe/observe.dart';
-import 'package:observe/mirrors_used.dart'; // for smaller code
-
-class Monster extends Unit with ChangeNotifier {
-  int _health = 100;
-  @reflectable get health => _health;
-  @reflectable set health(val) {
-    _health = notifyPropertyChange(#health, _health, val);
-  }
-
-  void damage(int amount) {
-    print('$this takes $amount damage!');
-    health -= amount;
-  }
-
-  toString() => 'Monster with $health hit points';
-}
-
-main() {
-  var obj = new Monster();
-  obj.changes.listen((records) {
-    print('Changes to $obj were: $records');
-  });
-  // Schedules asynchronous delivery of these changes
-  obj.damage(10);
-  obj.damage(20);
-  print('done!');
-}
-```
-
-**Note**: by default this package uses mirrors to access getters and setters
-marked with `@reflectable`. Dart2js disables tree-shaking if there are any
-uses of mirrors, unless you declare how mirrors are used (via the
-[MirrorsUsed](https://api.dartlang.org/apidocs/channels/stable/#dart-mirrors.MirrorsUsed)
-annotation).
-
-As of version 0.10.0, this package doesn't declare `@MirrorsUsed`. This is
-because we intend to use mirrors for development time, but assume that
-frameworks and apps that use this pacakge will either generate code that
-replaces the use of mirrors, or add the `@MirrorsUsed` declaration
-themselves.  For convenience, you can import
-`package:observe/mirrors_used.dart` as shown on the first example above.
-That will add a `@MirrorsUsed` annotation that preserves properties and
-classes labeled with `@reflectable` and properties labeled with
-`@observable`.
-
-If you are using the `package:observe/mirrors_used.dart` import, you can
-also make use of `@reflectable` on your own classes and dart2js will
-preserve all of its members for reflection.
-
-[Tools](https://www.dartlang.org/polymer-dart/) exist to convert the first
-form into the second form automatically, to get the best of both worlds.
-
-[Observable]: http://www.dartdocs.org/documentation/observe/latest/index.html#observe/observe.Observable
-[Observable.dirtyCheck]: http://www.dartdocs.org/documentation/observe/latest/index.html#observe/observe.Observable@id_dirtyCheck