Modify the program to use arguments and add functions "head_queue" and "print_queue".

	modified:   main.c
        Add arguments :
            -h, --help to print help.
            -t, --test [E1, E2, ..., EN] to test the stack with the elements [E1, E2, ..., EN].
            -s, --speed [N] to compute [N] insertions and [N] deletions and print the speed for each steps.
	modified:   queue.c
        Add function "print_queue" to print the queue.
        Add function "head_queue" to get the element at the head of the queue.
	modified:   queue.h
        Add functions prototype "print_stack" and "top_stack".
        Modify the names of functions "push_queue" and "pop_queue" for "enqueue_queue" and "dequeue_queue".