[FIX] Fix trackerfield Dynamic-Item-List. IMPORTANT: This fix saves the itemId of the referenced Item, not the native value! Thus it will break existing usecases.
Improvements/tested combinations: One can assign multiple DIL-Fields to one selection field (before it was just one).
Filterfield Combinations: category/category, itemlink/itemlink, itemlink/textfield (other equal fieldtypes should work as well). Category can only be used with category for security. 
Displayfields (to make the selection from) : category, itemlist, itemlink, textfield (other simple fields should work).