Feature: responsive design

**NOTE:** This PR is branched off of my other pending PR and won't be ready to merge until that one is done.

This adds some quick responsive styles to the app! Primarily focused on the user-facing end, and not the admin section (the couple of problem areas there can be cleaned up later).

Screenshots:

![screen shot 2014-03-17 at 3 20 04 pm](https://f.cloud.github.com/assets/808159/2442473/aff8fa24-ae22-11e3-8918-254499288962.png)
![screen shot 2014-03-17 at 3 20 24 pm](https://f.cloud.github.com/assets/808159/2442474/b126478a-ae22-11e3-979f-a6b645566fa5.png)
![screen shot 2014-03-17 at 3 20 46 pm](https://f.cloud.github.com/assets/808159/2442475/b2abbfea-ae22-11e3-91c3-aa84a5e138fb.png)

/cc @cherimarie @eastridge