Stand alone muon reconstruction cleaning for 72x

First step into the track to cure the "close-by muons" inefficiency.
For details see:
https://indico.cern.ch/event/331640/contribution/4/material/slides/0.pdf
Originally based on: HuguesBrun/cleanningBySegIn720
Target is 720pre3
I didn't mean to ask to change the PR again but take advantage when lines of code are updated anyway (or indeed a new PR/s/ can deal with such code optimizations).