v3.3.1 - Strict threshold for each moveable layout

Fix dragged siblings boundaries calculations (#421)

• Fix dragged siblings' boundaries when it calculates width and height.
• Fix isLeavingFromHead and strict index to zero.
• Remove unnecessary conditions in isOutThreshold.
• Change threshold to include bottom/right or four directions moving away from two points approach.

Add grid position to each cell and use private hashes for util classes (#425)

• Fix coordinates interface in the core.
• Add a grid for each cell and one for each sibling.
• Enhance Core interface documentation.
• Use private hashes for util classes.

Remove isDraggedOutPosition and isDraggedOutContainer (#419)

Use SWC for Jest and remove Babel (#424)