Refactored application Javascript

* Add autocomplete specific manifest file
* Add models Javascript file
* Use underscore.js templates
* Add class to translate json from Yammer api to scheddo models
* Add submit and render methods to objects bound to autocomplete menu
* Rename autocomplete.get to autocomplete.rank
* Refactor yammer_api.js and yammer_autocomplete.js
* Add yeild(:javascript) call for easy custom manifest use
* Refactor existing javascript specs and create new ones where necessary
* beautified yam.js spec asset
* Remove underscore Ruby gem
* Add underscore.js