Add current location to the map

Show your current location on the static map.

I think this thing is pretty neat. I played around with it today and found that as I tapped around a few different nearby cafes, I kept having to re-orient myself on the map since it re-draws and re-centers on each cafe... so I thought it would be nice to show your current location on the static map. The marker I chose is just a small empty pin. Not sure if you want pull requests or not so no big deal to reject, or replace with anything else.

Here's what it looks like:
![coffeedex_curloc](https://cloud.githubusercontent.com/assets/1214350/5256569/9be054dc-7998-11e4-8e6b-cfb522460c01.png)