THistPainter fixes, ROOT-9655 (#3150)
THistPainter fixes, ROOT-9655 (#3150)

* address issue https://sft.its.cern.ch/jira/browse/ROOT-9655

* add the documentation of the new options

root-mirror/root,karies/root,root-mirror/root,root-mirror/root,karies/root,root-mirror/root,olifre/root,karies/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,root-mirror/root,karies/root,karies/root,olifre/root,root-mirror/root,karies/root,karies/root,olifre/root,olifre/root,karies/root,olifre/root,root-mirror/root,olifre/root,karies/root,olifre/root,olifre/root,karies/root,karies/root,olifre/root,root-mirror/root,root-mirror/root