Add simple unitDates testing
Treat 'Bestandslaufzeit' differently from 'Provenienzlaufzeit' in unitdate (not done yet)
Separate Bestandslaufzeit unitdates from other dates (tested and working)
Change property 'unitDates' to 'hasDate' for value 'UNKNOWN date'
added xsl to remove empty tags from BA file
BundesarchiveTest not running
Merge branch 'BA-oneUnitDate' of github.com:bencomp/neo4j-ehri-plugin into BA
changed the bundesarchiv xml file to reflect the changes as would have been performed by remove_empty_tags.xsl
the end of a dateperiod is at the end of the year or month mentioned