Star stories

I'm going to add a feature that you can **starred a story** which you **like** just like GR. So that you can set all the stories you like into a list. I have already

- Add a new `/starred` page to show all starred stories
- Add `star` option to the story's action bar
- Add a new button link to `/starred` page
- Add English and Chinese locales

Known problems
- Localized text for some languages are missing
- Need write some tests for this new feature

Some screenshots

- New button which use `icon-star`

![feed_bar](https://f.cloud.github.com/assets/1213389/521167/09760e74-bf78-11e2-9c3f-ec4470bc32c2.png)
- `star` option's two statuses

![star](https://f.cloud.github.com/assets/1213389/521168/471f38b8-bf78-11e2-8e2b-39a4b13a4447.png)
![starred](https://f.cloud.github.com/assets/1213389/521170/5785c0fa-bf78-11e2-91f6-b86a2629ddd9.png)

This feature still need some work to do. And I'm looking forward to your **advice**.