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
I know this isn't part of this PR but this is the first I've noticed it: the filename is StdDev.h but the class name is StDev.  This violates our Coding Standard, section 2.1.2.

Does not block this PR.