Backport of tau-decay bug fix and exotica tuning

This PR include back-port of PR 4877 and 5119 done by hand:

1) Fixed problem of rare crash in tau-decay validation when tau decay happens outside volume where generators decay all unstable particle. This rare cases of large decay range due boost of tau, D, B more frequently happens at 13 TeV.
2) A fragment used for simulation of exotica has been revised and cleaned up according to 7_X_Y SIM.
Custom Physics List printpout at initialisation is moved from debug to info and a bit cleaned up.
GFlash is added to the list of processes in process enumeration table.
3) New lumi monitors have small acceptance, so ordinary simulation is very ineffective. In this PR a new filter allowing selection of primary particles is added. By default this filter is not enabled, so no effect for mainstream production.