enable output specification and directory creation in PIDCalib
This adds features to control the output of PerformMultiTrackCalib:
- specify the open mode of the output file
- name the output tree
- put the output tree in a directory hierarchy
It also allows MakePerfHistsRunRange to create the output directory if it doesn't exist and updates both files to follow PEP8 guidelines.
Edited by Michael Kent Wilkinson