update ember to 1.8.0-beta.5

- No more script tags for metamorphs!!
- Fix deprecation: App.NewNoteTextArea was a global view which is now
  deprecated. Change it to a component. The benefit of the component is
  that it can use `sendAction` to trigger a controller action.
- Fix deprecation: Don't use global App.user in handlebars. Instead use
  the `loggedIn` property on the controller.