Fix move operations when batched with deletes
Fix move operations when batched with deletes

Since deletes happen before moves, indexPathBeforeUpdate.item may no
longer point to correct index, so search for the object we're looking
for and use its index.

zace-yuan/PSTCollectionView,zjh171/PSTCollectionView,godLoveLucifer/PSTCollectionView,Anish-kumar-dev/PSTCollectionView,Kevin775263419/PSTCollectionView,steipete/PSTCollectionView,jianwoo/PSTCollectionView,niuxinghua/PSTCollectionView,ba01ei/PSTImprovedCollectionView,CorzFree/PSTCollectionView