Fix tests for Handlebars 2.0
Merge pull request #405 from tricknotes/fix-tests-for-hbs-2.0

Fix tests for Handlebars 2.0
Use ember.debug.js if it exist

`ember.js` is deprecated in favor of `ember.debug.js`
later than Ember.js 1.10.0.beta.1.
* https://github.com/emberjs/ember.js/issues/9830
* https://github.com/emberjs/ember.js/pull/9845
Support ember.debug.js for generator