Some follow-up tweaks from initial transformers

- Suppressed info message when compiling without using auto_injector, to eliminate unnecessary messages when compiling with Angular. Will switch to logging level fine which is not emitted by default once this moves to barback 0.12.
- Removed the @MirrorsUsed statement- ideal scenario is that mirrors are not encountered at all in which case this should not be there. Now that Angular is moving towards no mirrors, this gets in the way.
- Removed the generated injector module- I don't think this serves a purpose.
- Added explicit barback dependency.