Added toJson() method to generate the JSON representation of a Point.
Added toJson() method to generate the JSON representation of a Polygon.
Added readMappingData() and loadDistrictData() private methods.  Reformatted code.
Changed --json option to --maps.  Now writing map data as JSON instead of CSV.
Added writeCoordinatesAsJson() and getPolygon().
Fixed centering problems by pre-centering state map first, then zoom-to-extent after markers are set.