issue #49: change name of chronologicalItem to chronItem
issue #49: change name of chronologicalItem to chronItem

to keep in sync with EAC-CPF

SAA-SDT/EAD-Revision,SAA-SDT/EAD3,SAA-SDT/EAD-Revision,informaticmonad/EAD3,informaticmonad/EAD3,SAA-SDT/EAD3