Several editors on the same page

This will allow to have several editors on the same page, plus will allow to edit an issue and comment at the same time. Ref #318

![screenshot_1](https://f.cloud.github.com/assets/3051676/2490311/e72f22c0-b1a1-11e3-9ad0-66c505aafdf9.png)

This could be translated.
Since we probably not moving JS code to JS files in the foreseeable future... we should use our Twig translator method here...