In 'angular2/di' the symbol:
- Inject is a decorator
- InjectAnnotation is an annotation
Internally one an get a hold of annotations without *Annotations appened
(to make ts2dart work without workarounds) by importing from
'angular2/src/di/annotations_impl' instead of 'angular2/di'. This is
needed only for users that transpile through TS and through ts2dart.
Previously, getting testability was `window.angular2.getTestability`
This was because the plan was to export the API to the window as
angular2. However, the decision was changed to make this just `angular`
in 3177576ad6
To decouple testability from the rest of the Angular API, just make it
one function, `window.getAngularTestability`.
