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/112444/4878251/6cbca498-6305-11e4-8261-3fdce02f680a.png)
![rfay_screenshot__2014-11-02_at_7_55_49_pm](https://cloud.githubusercontent.com/assets/112444/4878252/6cc13152-6305-11e4-9e8c-d30863ccecf6.png)