[Not merging into master] Navigation prototype: remember accordion state

![screen shot 2014-06-23 at 17 41 02](https://cloud.githubusercontent.com/assets/1492162/3360677/5d6ee154-faf5-11e3-8c06-17a092608f4e.png)

we're doing some nav bar prototypes. this code is meant to be refactored if we agree it's worth having in our master