Fix 1271: NPE getting location service for map
Added NPE check and a toast. The app is unusable for anyone in this case, and we don't do strict checking for running the app on devices with missing services that are critical to to the app. So at least they will see a toast before it crashes somewhere else in the code.
Merge pull request #1303 from garvankeeley/1271-client-npe-gps-provider

Fix 1271: NPE getting location service for map