Now actually using the GeoPrecision setting.

* All settings are static
* Events on setting changes
* MainPage listens to GeoPrecision changes and reacts accordingly
Added an "Auto-zoom" option

Also fixed a couple of Code Analysis warnings
Redid the location loading and geohash loading code, which fixes #2.

There is now a separate button to reload the location. The settings are kind of a mess right now - they seem to work after much hassle, but I'm not using the GeoPrecision option right now, and I think I'm going to change that to a simple checkbox.