Adding UI for OS feed items.

#3455 

I used a custom menu item because the layout of the context system had some css problem and it was quicker for me to create a menu item with a custom CSS code.

![engadget rss](https://f.cloud.github.com/assets/1222368/982713/3b263218-0817-11e3-924e-2e83905d477c.png)
![new york rss](https://f.cloud.github.com/assets/1222368/982714/3b280980-0817-11e3-89fe-a12fe761c8b6.png)