improved use of MovingMinMaxAvg<> for better performance

* tweaked options of MovingMinMaxAvg<> to have better performance with same results
* added timing results for the network vs stats collection so we can see if stats collection is really bogging down system
You're calling usecTimestampNow() twice in rapid succession.  Was this accidental or on purpose?  You could just say:  int actualGap = statCalculationStart - last;

This doesn't block the merge, but I thought I would point it out just in case it was accidental.