load mapnik xml synchronously (we have no other safe choice for now) - closes #58 - refs mapnik/mapnik#1459
load mapnik xml synchronously (we have no other safe choice for now) - closes #58 - refs mapnik/mapnik#1459

tomhughes/tilelive-mapnik,wsw0108/tilesource-mapnik,CartoDB/tilelive-mapnik,mapbox/tilelive-mapnik,dshorthouse/tilelive-mapnik