PreStepPoint quantities in StepHistogramTool
- kinetic energy in current step,
- volume of the current step,
- step position.
For the process corresponding to the current step "PostStepPoint" remains to be used. I also added kinetic energy at the end of the step (using the "PostStepPoint") because it adds some interesting info. This is how it was calculated before, but I did not want to completely remove it, so now we have both pre- and post-step kinetic energy.