code: function parseString(xml, cb) {
      return fastxml2js.parseString(xml, function(err, data) {
          //So that it's asynchronous
          process.nextTick(function() {
              cb(err, data);
          });
      });
  }
docs: Callback after xml is parsed
  @callback parseCallback
  @param {string} err Error string describing an error that occurred
  @param {object} obj Resulting parsed JS object
   
  Parses an XML string into a JS object
  @param  {string} xml
  @param  {parseCallback} cb