issue #5409
`notifications.showErrors` was historically used to display multiple error notifications whether from validation errors or responses form the API. This usage needs to be reviewed as inline validations should handle the validation side and we should be displaying alerts for actual errors.
Eventually `notifications.showErrors` should be left unused and therefore removed.
issue #5409
- change persistent/passive notification status to alert/notification
- replace showSuccess/Info/Warn/Error with showNotification/showAlert
- fix and clean up notification/alert components
No Issue
- Switches to the newer style of dependency injection.
- Instead of injection Controllers via "needs," use
Ember.inject.controller().
- Get rid of initializers that were only injecting objects
into various factories. Converts these objects into Ember.Service
objects and declaratively inject them where needed via
Ember.inject.service(). The added benefit to this is that it's no
longer a mystery where these properties/methods come from and it's
straightforward to inject them where needed.