Mobile support

This is the start of mobile support for notifications.

![screen shot 2013-11-20 at 2 40 51 pm](https://f.cloud.github.com/assets/173/1587219/f4b89af6-5234-11e3-9580-67079d262d2b.png)

![screen shot 2013-11-20 at 2 41 27 pm](https://f.cloud.github.com/assets/173/1587221/fa1263f6-5234-11e3-86cd-fdd635a1e99d.png)


# TODO

- [ ] fix browser's back button when viewing notification details
- [ ] moar better mobile interactions
- [ ] swipe to next/prev notification
- [x] close nav after selecting an item