Fix infinity loop when max_size is zero

[defacedvr]

Max_size should be non_neg_integer
Explicitly handle max_size=0 and do nothing but return same struct

[defacedvr]

Hi. What you think about such changes? I found it pretty usable some times to create deque with max_size=0 and use as bounded queue without worries.
When size depend on configuration, you will be able to simply provide 0 and use it like /dev/null.

Anyway, currently it goes to infinity loop, when max_size <= 0

[jhgg]

Can you update tests?

[defacedvr]

Sure. I'll add some tests a little bit later