UBItem:
renamed UBItem->clone_id to UBItem->cloned_from
removed cloned_from link from clones when deleting parent (reset to 0)
ClipitPerformanceItem:
added category
ClipitMaterial:
Added this common class for ClipitFile, ClipitStoryboard and ClipitVideo
added common API exposure methods
z04/views/default/forms/publications/evaluate.php and z04/views/default/publications/view.php:
renamed performance_array -> performance_item_array