Improve JSONLDRelatedField to_internal_value()
Improve JSONLDRelatedField to_internal_value()

Added a better checking of correct input format, and changed the
whole logic to a bit simpler one.

tuomas777/linkedevents,tuomas777/linkedevents,City-of-Helsinki/linkedevents,aapris/linkedevents,aapris/linkedevents,City-of-Helsinki/linkedevents,aapris/linkedevents,City-of-Helsinki/linkedevents,tuomas777/linkedevents