Changed how time is measured in HashedCircularPriorityQueues: time is no longer based on the system clock, but on the latest time seen as a timestamp for a probing item.  This can be spoofed using the local clock by the code utilising the HashedCircularPriorityQueue for systems not using timestamps that persist between operators.  However, in systems where universal timestamps are used, this removes the problem of non-synchronised clocks, and also allows for the system to ignore lag (to a small degree), as the operator state only keeps up with the latest input, rather than overtaking it as would happen with the delay produced by chaining operators.