bundle update
Use ember-middleman to manage ember-source

* Remove vendor/{ember-1.7.0.js,handlebars-1.3.0.js}
* Load example files using ERB instead of XHR.
Extract templates for builds app as separated JS files
Use gems hosted by rails-assets instead of vendor scripts
Remove unused vendor script
Update Ember.js to 1.8.0
Merge pull request #1773 from tricknotes/update-vendor-assets

Update some libraries including Ember.js