Add GoogleMaps API to dive site index

https://trello.com/c/BCpf77el/24-create-map

![image](https://cloud.githubusercontent.com/assets/8681076/5129000/db49dee4-70ac-11e4-9df3-1e9b8a2a59a0.png)
What's the purpose of this div and the one inside it? Does it do anything?