Refactored class hierarchy for various DSpace Objects
Item will always call super __init__ even if passed empty data. This ensures new items won't accidentally use a class static metadata dict, and will have all members properly instantiated in DSpaceObject.__init__
update_dso made more stable and update_item updated to call it properly
Various fixes:
Itemwill always call super__init__even if passed empty data. This ensures new items won't accidentally use a class static metadata dict, and will have all members properly instantiated inDSpaceObject.__init__update_dsomade more stable andupdate_itemupdated to call it properly