Fix/multiple work relation identifiers
Created by: cleshams
Allows processing of multiple values for WorkIdentifier in the case where multiple are found within the RelatedWork property
<relatedwork>
<x454>01</x454>
<workidentifier>
<b201>01</b201>
<b233>www.stisonbooks.com Content Identifier</b233>
<b244>PLUTO-61647</b244>
</workidentifier>
<workidentifier>
<b201>01</b201>
<b233>www.stisonbooks.com Work Identifier</b233>
<b244>PLUTO-62b857cf8c406</b244>
</workidentifier>
</relatedwork>