Datelines & Cards tweaks

- [new] Cards are easier to click (image + headline are wrapped in an anchor)
- [new] Visited state on cards
- [fix] All datelines look the same (same type size and spacing between icon & text)
- [fix] Time zones can't be widows anymore (an unbreakable space is now inserted between the time and the timezone)

## Timezone widows

Before, "GMT" was often a widow on mobile. Now, it's always attached to the time:
![screen shot 2013-11-25 at 19 20 17](https://f.cloud.github.com/assets/85783/1616189/ab56dc4e-5606-11e3-810e-b8b1e10b4066.png)

![ ](http://2.bp.blogspot.com/-Y9snnvYqSi8/UpNbPHcWa-I/AAAAAAABDlE/YWTGq68wj2o/s1600/44.gif)