Add optional capacity to queue

[polytypic]

This PR adds optional capacity argument to Queue.create and Stack.create allowing one to create a bounded queue/stack.

TODO:

• Add capacity to stack.
• Allow setting the capacity.
  • If capacity is less than length then new elements cannot be added to the queue/stack.
  • Capacity can be set to 0 to effectively "close" the queue/stack.
• Test operations with capacity <> Int.max_int