Feature/symfony2 rest api

@brettminnie Actually, the reason why it was multiple is because the field name in the response is plural, thoughts? I might revert the `singular` commit?

Response example...

```javascript
{
  "version": "-- unknown --",
  "data": [
    "---- No Changelog ----"
  ],
  "actions": {
    "changelog": "/changelog"
  }
}
```