ember-engine + ember-page-title fails

Stack trace

```javascript
ember.debug.js:26518 Error: Assertion Failed: Expected component:head-content to resolve to an Ember.Component but instead it was [object Object].
at assert (ember.debug.js:13695)
at validateType (ember.debug.js:13002)
at Class.resolve (ember.debug.js:12704)
at resolve (ember.debug.js:10640)
at Registry.resolve (ember.debug.js:10311)
at Registry.resolve (ember.debug.js:10315)
at Container.factoryFor (ember.debug.js:9720)
at Class.factoryFor (ember.debug.js:37715)
at Class.componentFor (ember.debug.js:45690)
at lookupComponentPair (ember.debug.js:47322)
```

``` javascript
ember.debug.js:26518 Error: Could not find module `test-engine/templates/head` imported from `test-engine/components/head-content`
at missingModule (loader.js:247)
at findModule (loader.js:258)
at Module.findDeps (loader.js:168)
at findModule (loader.js:262)
at requireModule (loader.js:24)
at Class._extractDefaultExport (index.js:392)
at Class.resolveOther (index.js:113)
at Class.superWrapper [as resolveOther] (ember.debug.js:45379)
at Class.resolve (ember.debug.js:12695)
at resolve (ember.debug.js:10640)
````