Code review comment for lp:~hazmat/txzookeeper/distributed-queue

[12] I added some doc strings to the get request which documents all the variables, if this is insufficient for clarity let me know, and i'll do a round of variable renames.

[14] Per out discussion on reliable processing/consumption of queue items, i've added the reliable queue and serialized queue implementations. A new serialized queue implementation utilizing a lock is something i'll address in a future branch (added bug:592266), the implementation as is suffers from a lot of pointless contention among consumers waking up from watches without any work they can proceed with, nonetheless its functional.