Minor changes in the library.

Issue : When the dragging is initiated on the empty area the closest cell is matched.
Resolution : Need to find the exact cell.

Issue: Let us consider the collection view is just the bottom half of the window. Lets say user wants to drag the last cell to the first , say 100 cell to the 1. User initiates the dragging and moves the cell to the top of the collection view. As the collection view is just the bottom part of the window the mock cell gets clipped.
Resolution : Add mock cell to the window.

Issue: Applying transform for the mock cell blurs the view.
Resolution: Provided the optional delegate method so user can provide his/her own view and also changing properties when needed like font colour or background colour.