Fixed it so that if an object is NULL its value is written as an empty string to the XML instead of the script crashing.
Fixed it so that if an object is NULL its value is written as an empty string to the XML instead of the script crashing.

manumaticx/ti.js2xml,jlipps/node-js2xmlparser,michaelkourlas/node-js2xmlparser,manumaticx/ti.js2xml,michaelkourlas/node-js2xmlparser,bschaepper/node-js2xmlparser