Revert "Use deepcopy for rollbacks"

This reverts commit 38fac4eb8860f1513627ebe92c8d5df1766e8476.
Store (selected, parent, index) for all actions
Use separate alphabets for different constants
Add rollback to Insert action
Add rollback to Rename action
Add rollback to Paste action
Add rollback to MoveUp/MoveDown actions