Deque class

The Deque class is a "double-ended Queue," and not to be confused with the word "dequeue." The double-ended queue allows one to add values to the front or rear of the queue, and allows for values to be removed from the front or rear of the queue.

For the Deque class write:

• the Deque constructor
• add_front(item)
• add_rear(item)
• remove_front()
• remove_rear()
• size()
• is_empty()