Update charted to 0.4.8 and roll

packages/observe/CHANGELOG.md

-#### 0.13.1+3
-
- * Sorting an already sorted list will no longer yield new change notifications.
-
-#### 0.13.1+2
-
- * Update to analyzer '<0.27.0'
-
-#### 0.13.1+1
-
- * Update to logging `<0.12.0`.
-
-#### 0.13.1
-
- * Update to analyzer `<0.26.0`.
-
-#### 0.13.0+2
-  * Fixed `close` in `PathObserver` so it doesn't leak observers.
-  * Ported the benchmarks from
-    [observe-js](https://github.com/Polymer/observe-js/tree/master/benchmark).
-
-#### 0.13.0+1
-  * Widen the constraint on analyzer.
-
-#### 0.13.0
-  * Don't output log files by default in release mode, and provide option to
-    turn them off entirely.
-  * Changed the api for the ObserveTransformer to use named arguments.
-
-#### 0.12.2+1
-  * Cleanup some method signatures.
-
-#### 0.12.2
-  * Updated to match release 0.5.1
-    [observe-js#d530515](https://github.com/Polymer/observe-js/commit/d530515).
-
-#### 0.12.1+1
-  * Expand stack_trace version constraint.
-
-#### 0.12.1
-  * Upgraded error messages to have a unique and stable identifier.
-
-#### 0.12.0
-  * Old transform.dart file removed. If you weren't use it it, this change is
-    backwards compatible with version 0.11.0.
-
-#### 0.11.0+5
-  * Widen the constraint on analyzer.
-
-#### 0.11.0+4
-  * Raise the lower bound on the source_maps constraint to exclude incompatible
-    versions.
-
-#### 0.11.0+3
-  * Widen the constraint on source_maps.
-
-#### 0.11.0+2
-  * Widen the constraint on barback.
-
-#### 0.11.0+1
-  * Switch from `source_maps`' `Span` class to `source_span`'s `SourceSpan`
-    class.
-
-#### 0.11.0
-  * Updated to match [observe-js#e212e74][e212e74] (release 0.3.4), which also
-    matches [observe-js#fa70c37][fa70c37] (release 0.4.2).
-  * ListPathObserver has been deprecated  (it was deleted a while ago in
-    observe-js). We plan to delete it in a future release. You may copy the code
-    if you still need it.
-  * PropertyPath now uses an expression syntax including indexers. For example,
-    you can write `a.b["m"]` instead of `a.b.m`.
-  * **breaking change**: PropertyPath no longer allows numbers as fields, you
-    need to use indexers instead. For example, you now need to write `a[3].d`
-    instead of `a.3.d`.
-  * **breaking change**: PathObserver.value= no longer discards changes (this is
-    in combination with a change in template_binding and polymer to improve
-    interop with JS custom elements).
-
-#### 0.10.0+3
-  * minor changes to documentation, deprecated `discardListChages` in favor of
-    `discardListChanges` (the former had a typo).
-
-#### 0.10.0
-  * package:observe no longer declares @MirrorsUsed. The package uses mirrors
-    for development time, but assumes frameworks (like polymer) and apps that
-    use it directly will either generate code that replaces the use of mirrors,
-    or add the @MirrorsUsed declaration themselves. For convinience, you can
-    import 'package:observe/mirrors_used.dart', and that will add a @MirrorsUsed
-    annotation that preserves properties and classes labeled with @reflectable
-    and properties labeled with @observable.
-  * Updated to match [observe-js#0152d54][0152d54]
-
-[fa70c37]: https://github.com/Polymer/observe-js/blob/fa70c37099026225876f7c7a26bdee7c48129f1c/src/observe.js
-[0152d54]: https://github.com/Polymer/observe-js/blob/0152d542350239563d0f2cad39d22d3254bd6c2a/src/observe.js
-[e212e74]: https://github.com/Polymer/observe-js/blob/e212e7473962067c099a3d1859595c2f8baa36d7/src/observe.js