Use the UICollectionViewFlowLayout’s `sectionInset` property instead of UICollectionView’s `contentInset` when calculating the maximum width of a collection view cell
Refactor sizeForItemAtIndexPath: to make it less likely that an invalid size is returned.
Instead of asking the MBContactCollectionViewContactCell for its size, just ask for it’s width.  The MBContactCollectionView knows how tall cells should be.
Further refactor sizeForItemAtIndexPath since the item’s width is the only thing that is variable, cell height is constant per MBContactCollectionView instance.
Merge pull request #54 from Citrrus/feature/fix_collection_view_insets_miscalculation

Feature/fix collection view insets miscalculation