Data Structure Library

Implements Array, Stack, Queue, Deque, LinkedList, DoublyLinkedList, List(Dynamic Array).

Common functions for each class.

1. first() Gets the first element.
2. last() Gets the last element.
3. add() Adds element to list in the last.
4. insert(index) Inserts element at a specific index.
5. indexOf(element) Returns the index of first apprearance of the element.
6. remove(element) Removes the first appearance of the element.
7. removeAt(index) Removes the element present at the given index.
8. sort() Sorts the container.