2020-05-12 Gauss v54r2

This version uses LHCb v51r0, Gaudi v33r0, Geant4 v106r1 and LCG_96b with ROOT 6.18.04.

The following generators are used from LCG_96b: - pythia8 240.lhcb4, lhapdf 6.2.3, photos++ 3.56.lhcb1, tauola++ 1.1.6b.lhcb - pythia6 427.2.lhcb - herwig++ 2.7.1, thepeg 2.1.5 - crmc 1.5.6, hijing 1.383bs.2, starlight r300 - rivet 2.7.2b, yoda 1.7.7

while the followings are built privately: - EvtGen with EvtGenExtras, AmpGen, Mint - BcVegPy, GenXicc - SuperChic2, LPair - MIB

This version is released on master branch. Built relative to Gauss v54r1, with the following changes:

New features ~"new feature"

• ~"Detector simulation" ~Geant4 | Add G4 classes for Hidden Valley Particles, !567 (@cvazquez) [LHCBGAUSS-1529]
• ~Generators ~IFT | Added Pythia8Angantyr.py to LbPythia8 configuration, !570 (@baudurie)

Fixes ~"bug fix" ~workaround

• ~Configuration | RootInTES fix with support for string sequencer members, !578 (@dmuller)
• ~Generators ~Decays | Fix missing initialisation of constants for event generation, !600 (@kreps)

Enhancements ~enhancement

• ~Generators ~Decays | Access the polarisation in EvtGen for spin 1/2 baryons, !561 (@elniel) [LHCBGAUSS-1827]
• ~Generators ~IFT | Change of default PDF for SuperChic2, !589 (@crsanche)

Code cleanups and changes to tests ~modernisation ~cleanup ~testing

• ~Generators | Fix GeneratorAnalysis for particle gun and tool for EvtGen testing., !595 (@kreps)