protect from overflow in Image.fromSVG - refs #740
protect from overflow in Image.fromSVG - refs #740

tomhughes/node-mapnik,CartoDB/node-mapnik,CartoDB/node-mapnik,mapnik/node-mapnik,CartoDB/node-mapnik,CartoDB/node-mapnik,tomhughes/node-mapnik,CartoDB/node-mapnik,tomhughes/node-mapnik,tomhughes/node-mapnik,mapnik/node-mapnik,mapnik/node-mapnik,tomhughes/node-mapnik,mapnik/node-mapnik,mapnik/node-mapnik