Fix issues with the cost monitoring plotting

The automatic rangig caused extended the range beyong the "normal" range of the histgrams for some histograms. Then the, frankly unwanted, root behaviour of then including the underflow bin cause issues, since the histogram underflow limit is always set to -1666.57.

This adds an additional check that prevents the range ever going below the actual histogram displayed limit for the time.

Also, because the histograms now very sensibly, always have logarithmic binning we now divide by the bin width by default.

This causes an issue with the computation of the means, so not the means are calculated correctly using the integrals of the histograms rather than the naive root calculation.