Irc: block when the queue is empty instead of needlessly polling it
Irc: block when the queue is empty instead of needlessly polling it

Rework Irc.processQueue() to block when the queue is full, and abort if the item "None" is sent to it.
To make sure that the None isn't caught by a full queue or pushed back by other elements, this modifies queue.Queue's underlying deque instance directly.

Closes #459.

GLolol/PyLink