Use Chosen instead of tags

@markrickert how do you feel about this? trying to figure out if there's a less crowded way to explore/show tags:

![screen shot 2014-01-17 at 10 05 13 am](https://f.cloud.github.com/assets/153704/1942961/10a1704a-7fa2-11e3-8bf2-6477bbd06240.png)

![screen shot 2014-01-17 at 10 05 19 am](https://f.cloud.github.com/assets/153704/1942960/10909054-7fa2-11e3-91fa-5af846977b31.png)