Separate the requirements from the draft status in the composer

<del>Per @SamSaffron's [comment](https://github.com/ZogStriP/discourse/commit/b2ce1d574f2be24a35202a85a6571f81ca9bff0e#commitcomment-2940541): this separate the requirements from the draft status in the composer:</del>

![Screenshot_04_04_13_03_42](https://f.cloud.github.com/assets/362783/337244/5b428c04-9cc9-11e2-80c7-888b276f65c9.png)

<del>**Note:** I've modified the way the draft status (ie. `saving/saved/offline`) is cleared. 
It was cleared when the composer would get the focus and will now disappear **5 seconds** after being displayed.</del>

After some discussion, it appears that only one field is prefered. This PR only rename the div and a few methods to allow for a better understanding of the various components involved.