- The nPartPerCell was not updated correctly after each
  regrid step.

modified:   AmrOpal.cpp
modified:   AmrPartBunch.h
modified:   Distribution.cpp
modified:   Distribution.h
modified:   PartBunch.h
modified:   PartBunchBase.h
modified:   error.cpp
modified:   testAmrPartBunch.cpp
modified:   tracking_vis.py