BasicDoubleLinkedList

This generic double$-$linked implements the Java$$s Iterable interface and relies on a head $($reference to first element of the list$)$ and tail $($reference to the last element of the list$).$ Both the head and the tail are set to null when the list is empty. Both point to the same element when there is only one element in the list. A node structure has three fields: data, next and the previous references.