style(dart): Format with dartfmt v0.2.0

Format all pure Dart code with package:dart_style v0.2.0

Command:
```
find -type f -name "*.dart" | xargs dartformat -w
```

modules/angular2/test/di/binding_dart_spec.dart

@@ -40,7 +40,9 @@ main() {
 }
 
 class Foo {}
+
 class Bar extends Foo {}
+
 fn() => null;
 
 class Annotation {