Add max limit to the indication received queue

[KSchopmeyer]

Now that we have a queue to hold indications before being passed to the callbacks, the listener can overload thwat queue if indications are received at a rate faster than the callback function can process them. There should be the capability to set a maximum limit on the number of indications in the queue and either slow down acceptance or stop receiving indications.

The Python queue facility supports a Full concept for a queue so the question is exactly what should the listener do if the queue is full.

[andy-maier]

I suggest to not enable the limit by default, but to give the user an option to opt in for the limit, because enabling the limit also means the user needs to be prepared for the exception.