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.
Add two factory static functions to Injector: resolveAndCreate and
fromResolvedBindings.
We want to avoid resolution and flattening every time we create a new
injector. This commit allows the user to cache resolved bindings and
reuse them.
