Queue api

[jdavid]

We've now a Queue library implementing both FIFO and LIFO. The main difference is that FIFO has an extra index file that points to the first frame in the queue.

Add the ability to FIFO queues to pop the last item, as this is easy enough. Then review the API of both classes, we should have: peek_first, drop_first, peek_last, drop_last.

Remove the base class Queue, FIFO will inherit from LIFO. It just adds the index file and the peek/drop first functions.

[johnhulth]

Please explaian what you mean here??? ...can we just drop the FIFO as LIFO is implemented? W find LIFO more valuable since this indicate when last fram was sampled.

[jdavid]

This is only code clean-up, has no visible effect. Just noted it here so I don't forget.

[jdavid]

So low priority.