zonegrouptopology json parsing error

[daragallagher]

I think this change has occurred with a recent Sonos firmware update as I had also been using scripts to interact with the speaker http which broke recently while parsing the topology json.

TypeError: Cannot read property 'ZoneGroup' of undefined at parseXML (/home/pi/sonos/denysvitali/sonos-web/server.js:850:59) at Parser. (/home/pi/sonos/denysvitali/sonos-web/node_modules/xml2js/lib/parser.js:303:18) at Parser.emit (events.js:189:13) at SAXParser.onclosetag (/home/pi/sonos/denysvitali/sonos-web/node_modules/xml2js/lib/parser.js:261:26) at emit (/home/pi/sonos/denysvitali/sonos-web/node_modules/sax/lib/sax.js:624:35) at emitNode (/home/pi/sonos/denysvitali/sonos-web/node_modules/sax/lib/sax.js:629:5) at closeTag (/home/pi/sonos/denysvitali/sonos-web/node_modules/sax/lib/sax.js:889:7) at SAXParser.write (/home/pi/sonos/denysvitali/sonos-web/node_modules/sax/lib/sax.js:1436:13) at Parser.exports.Parser.Parser.parseString (/home/pi/sonos/denysvitali/sonos-web/node_modules/xml2js/lib/parser.js:322:31) at Parser.parseString (/home/pi/sonos/denysvitali/sonos-web/node_modules/xml2js/lib/parser.js:5:59) at exports.parseString (/home/pi/sonos/denysvitali/sonos-web/node_modules/xml2js/lib/parser.js:354:19) at Listener.listener.on (/home/pi/sonos/denysvitali/sonos-web/server.js:845:21) at Listener.emit (events.js:189:13) at Listener. (/home/pi/sonos/denysvitali/sonos-web/node_modules/sonos/lib/events/listener.js:63:12) at Parser. (/home/pi/sonos/denysvitali/sonos-web/node_modules/xml2js/lib/parser.js:303:18) at Parser.emit (events.js:189:13) at SAXParser.onclosetag (/home/pi/sonos/denysvitali/sonos-web/node_modules/xml2js/lib/parser.js:261:26) at emit (/home/pi/sonos/denysvitali/sonos-web/node_modules/sax/lib/sax.js:624:35) at emitNode (/home/pi/sonos/denysvitali/sonos-web/node_modules/sax/lib/sax.js:629:5) at closeTag (/home/pi/sonos/denysvitali/sonos-web/node_modules/sax/lib/sax.js:889:7) at SAXParser.write (/home/pi/sonos/denysvitali/sonos-web/node_modules/sax/lib/sax.js:1436:13) at Parser.exports.Parser.Parser.parseString (/home/pi/sonos/denysvitali/sonos-web/node_modules/xml2js/lib/parser.js:322:31)