cleanup obsolete PhysList and add G4Exp, G4Log to Urban93

[civanch]

Obsolete Physics Lists LHEP, LHEP_EMV, QGSP_BERT_EMLGG, QGSP_BERT_EMLGN, QGSP_BERT_EMLNoDel are removed.

UrbanMscModel93 was cleaned up: G4Exp and G4Log are used instead of std::log, std::exp, two short methods inlined.

Results should be unchanged only some CPU advantage. This PR should be merged only to 7_1_GEANT10

[cmsbuild]

A new Pull Request was created by @civanch (Vladimir Ivantchenko) for CMSSW_7_1_GEANT10_X.

cleanup obsolete PhysList and add G4Exp, G4Log to Urban93

It involves the following packages:

SimG4Core/PhysicsLists

@cmsbuild, @civanch, @Degano, @mdhildreth, @nclopezo can you please review it and eventually sign? Thanks.
You can sign-off by replying to this message having '+1' in the first line of your reply.
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[civanch]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_1_GEANT10_X IBs unless changes or unless it breaks tests.