Update Ember to 1.8.0.

Closes #4316
- Ember@1.8.0.
- Ember-Data@1.0.0-beta.11.
- Change templates to use new Ember.Select syntax and other minor
  cleanup.
- Adjust functional tests.
Merge pull request #4361 from jaswilli/ember18

Update Ember to 1.8.0.