Update select2 styles

:fork_and_knife: Add vendor select2 styles that make select2 look more consistent with Foundation's styles, which Supermarket users for its base styles, the new vendor styles are based on [this](https://gist.github.com/cviebrock/8056741). This is what it looks like now.

![screen shot 2014-07-23 at 10 36 58 am](https://cloud.githubusercontent.com/assets/316507/3675243/a05e72aa-127d-11e4-8843-2a57f88a4d5a.png)

![screen shot 2014-07-23 at 10 59 26 am](https://cloud.githubusercontent.com/assets/316507/3675247/a47806da-127d-11e4-9855-fffb022408de.png)

![screen shot 2014-07-23 at 10 56 20 am](https://cloud.githubusercontent.com/assets/316507/3675249/a86f6daa-127d-11e4-9dd4-ba811e068414.png)