Update xml2json.py: Work with Python >= 2.6
Update xml2json.py: Work with Python >= 2.6

Replace simplejson with json module
KaiyuWang16/xml2json,yfjd01/GitDocuments,KaiyuWang16/xml2json-1,metal-hero/tested_xml2json,noelpark/xml2json,haiyangd/xml2json-,metal-hero/tested_xml2json,metal-hero/tested_xml2json,hay/xml2json