allow cells to be deletable if dropped outside of UICollectionView bounds

Signed-off-by: Jared Allen <jared@redcact.us>
support AlterTranslation delegate method
support transform delegate method
should not use cell's opaque value to generate image.
fix transform delegate method
add transform duration configurable via datasource delegate method.
add podspec
fix podspec/sources
Add a hook that exposes the mock cell when dragging for animations