Backward scroll

[Serg-Pogrebnyak]

Please fix backward scroll... because if I want make backward scroll for example on 2-3 cell I can do this only on one cell, I made small research and found problem in MSCollectionViewPaging.swift in func getNewTargetOffset(startingOffset: CGFloat, velocity: CGFloat, targetOffset: CGFloat) -> CGFloat if I change var offset = max(targetIndex - currentIndex, 1) on var offset = max(abs(targetIndex - currentIndex), 1) all work correctly, please, check this. Thanks a lot)