Hepmc3 nightly fixes 23122020 part 1

In this MR, for the HepMC3 compatibility

• Update HepMC related types
• use more auto
• use std:: explicitely
• use free functions from the HepMC namespace
• removed a very poorly formatted comment with "<<<" and ">>>" which can be confusing in the context of git

marked as a Work In Progress

This merge request affects 5 packages:

• PhysicsAnalysis/D2PDMaker
• PhysicsAnalysis/D3PDMaker/TruthD3PDMaker
• PhysicsAnalysis/TruthParticleID/McParticleTools
• Reconstruction/iPat/iPatInterfaces
• Reconstruction/iPat/iPatTruthTrajectory

Affected files list will not be printed in this case

Adding @goetz as watcher

added Analysis JetEtmiss Reconstruction master review-pending-level-1 labels

CI Result SUCCESS (hash 2ce6bff4)

	Athena	AthSimulation	AthGeneration	AnalysisBase	AthAnalysis
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
AthAnalysis: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 25671]

Marked as Draft. Removing L1 review tag. Please tag for review after its ready to review. Thanks (L1)

added review-user-action-required label and removed review-pending-level-1 label

changed the description

unmarked as a Work In Progress

added review-pending-level-1 label and removed review-user-action-required label

MR looks good. Approving (L1)

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit 5084b79a

added sweep:ignore label