Corrected the error that scott hit with a coordinate value somehow being negative. Changed the coordinate system to evaluate both x and y simultaneously to stop the no redraw condition on vertical zones.  Partially addressed overlapping zones. That might need to be readdressed later if it becomes an issue where people are multizoning sections of the map.  Who the fuck would do that? As long as no other bugs are found then these changes need to be propagated over to the other similar files zone_stats for sure. #275