Improve convergence speed of CumulativeAverage
* tiny bug: initial value was considered a valid measurement * led to slow convergence, if actual measurements are large * also fixed a bug concerning the minimal/maximal elements
* tiny bug: initial value was considered a valid measurement * led to slow convergence, if actual measurements are large * also fixed a bug concerning the minimal/maximal elements
mentioned in commit a831b501
·mentioned in commit a831b501