progressive enhance to flexbox and fix layout on index

Long titles on narrow viewports are pushing the date to the next line, unevenly.
Added CSS Flexbox to better distribute space. 

I see you're not using prefixes so I leave it to you if you want to add them for other browsers. Will work on Firefox & Chrome. Falls back to float, current behavior, in other browsers.

Before: 
![screen shot 2014-02-27 at 12 48 06 pm](https://f.cloud.github.com/assets/63899/2282451/7438797e-9fae-11e3-840c-4421730b6757.png)

After: 
![screen shot 2014-02-27 at 12 48 11 pm](https://f.cloud.github.com/assets/63899/2282452/7a6973c0-9fae-11e3-8fb8-333d690c12e7.png)