Change a few non-standard Xalgo field names to standard UBL field names

[jpotvin]

Currently Xalgo contains some fields that do not conform with with UBL. Please change these non-standard Xalgo field names to standard UBL field names:

Change envelope:type TO envelope:DocumentType
Change IN and TO CountrySubentityCode
Change industry TO IndustryClassificationCode
Change TIMEZONE TO TimezoneOffset