Fix Undefined extended_entities

This should fix this notice:

> Undefined index: extended_entities
One more fix for encoding content
Use ParamConvert to simplify controllers

Following "best practices"
Remove @Template annotation

And follow best pratice http://symfony.com/doc/current/best_practices/controllers.html#template-configuration
Update deprecated method

Following best pratices on Form: symfony.com/doc/current/best_practices/forms.html
Quick cleanup on Formatter

Define abstract method that weren't used in the main class
Use moment.js instead of KnpTimeBundle

Moved the front logic to javascript
Add more information in the public page:
 - link to the website
 - items in the feed
 - clear link to the readable feed