Added user-badges component

I'm going to use this component in hero banners and also in the new flickr widget, so I think that may worth convert this tiny html into a component...

Also, we can extend it to be used in community. 
![screen shot 2014-06-20 at 11 39 31](https://cloud.githubusercontent.com/assets/1152640/3338749/347ccd52-f860-11e3-95c9-07ad04fe4fb7.png)

Can we use the `safe_image_tag` helper here? It works like this: https://github.com/lonelyplanet/rizzo/blob/8ca81752e2e4fc186c858a41e84b1e7ecc7c9298/app/views/components/cards/partials/_card_content.html.haml#L7

This is to stop a peculiar behaviour in rails where if the image src comes through as `nil` then the entire page 500s :/