Use new-style hook names for initialization

I've pulled the latest version of the ember starterkit yesterday and noticed that it doesn't work with emblem because of a removed (deprecated) hook: ```registerComponents```, which was renamed to ```registerComponentLookup```. I currently see this change only for the upcoming releases of ember, but the starterkit already contains those changes (although it says it's using v1.2.0).

This fix corrects the naming.