Show distance from device in both individual and cluster infoWindows

Fixes #96 

![rfay_screenshot_ 2014-11-02 at 7 54 52 pm](https://cloud.githubusercontent.com/assets/112444/4878239/076a9b18-6305-11e4-9216-7f4162e2f8c1.png)

![rfay_screenshot_ 2014-11-02 at 7 55 49 pm](https://cloud.githubusercontent.com/assets/112444/4878240/0d6ca1f0-6305-11e4-9ae1-b4bf4a6d16db.png)