Common "public facing" components

Things such as:

* Navigation bar (including logged out and logged in states)
* Footer

This should cover everything in #49.
From React's standpoint, they're just two different keys. Essentially as long as a key is unique among a set is unique React is happy. That being said, they're most likely different here because they were written by different persons in the documentation. (Or by a single distracted one!) Perhaps we should agree to use one or the other? I personally tend to prefer the Numbers.