Update handlebars version at about page

Handlebars 1.3.0 seems to work with Ember.js 1.4.0.
And all tests are passed in this version:
* https://github.com/emberjs/ember.js/blob/v1.4.0/Gemfile.lock#L48
Update handlebars version to 1.3.0 for example application
Merge pull request #1306 from tricknotes/update-handlebars

Update handlebars to 1.3.0