Engine#resolverFor()

This function defines the default lookup rules for container lookups:

• templates are looked up on Ember.TEMPLATES
• other names are looked up on the application after classifying the name. For example, controller:post looks up App.PostController by default.
• if the default lookup fails, look for registered classes on the container

This allows the application to register default injections in the container that could be overridden by the normal naming convention.