No default API URL, exit when not given

wiki-map.pl

@@ -49,6 +49,8 @@ GetOptions
 	'regiondir=s' => \$regiondir
 );
 
+$api_url // croak "Base API URL is required! Use --api-url to set
+
 my $grid = HexGrid->new(defaults => {
 		style => { 'stroke-width' => $border_width, stroke => $border_colour },
 		show_coords => $show_coords });