use Ember.get for case when prototype extension is not enabled
use Ember.get for case when prototype extension is not enabled

kimroen/ember-cli-document-title,lucas-clemente/ember-cli-document-title,lucas-clemente/ember-cli-document-title,rwjblue/ember-cli-document-title,kimroen/ember-cli-document-title,rwjblue/ember-cli-document-title,ssendev/ember-cli-document-title,abulrim/ember-cli-document-title,ronco/ember-cli-document-title,ssendev/ember-cli-document-title,abulrim/ember-cli-document-title,ronco/ember-cli-document-title