added at 117 xsl:if for vFieldValue so it is 'NA' when
 '@Value' is not found (this means item is an OC Null flavour)
added at 140 xsl:when for vFieldValue when date type, change to
 YYYY-MM-DD if date is DD-Mmm-YYYY (happens with insertaction-copy)
changed at 201 to check if dataframe is empty before trying to add
 any factors
added at 227 xsl:template for cleaning up dates