Adding in support for MultiPolygons.  Added higher-rez Offline Map

First, added in a lightly modified version of the iOS 50m geojson offline layer.  The only difference in this file is that we changed +/-90.0 and +/-180.0 coordinates with +/-89.9999 and +/-179.9999 respectively.  Android's map overlay API has a bug that completely omits polygons if they fall on the boundaries spherical coordinate system.  This was causing Antarctica to drop completely from the map.  

Second, added support for offline MultiPolygons in the offline map.  This allows for more sophisticated geojson structures to be utilized.