go-hepmc-dump command

go-hepmc-dump is a simple command to dump in an almost human-friendly format the content of a hepmc file. ex:

$ go-hepmc-dump foo.hepmc | head -n20

________________________________________________________________________________ GenEvent: #0000 ID= 111 SignalProcessGenVertex Barcode: 0

Momentum units:      GEV     Position units:       MM
Cross Section: 2.666668e+12 +/- 2.666668e+12
Entries this event: 129 vertices, 241 particles.
Beam Particle barcodes: 1 2
RndmState(0)=
Wgts(1)=(0,1.000000)
EventScale 1.438780e+00 [energy] 	 alphaQCD=4.519907e-01	 alphaQED=7.472465e-03
                                   GenParticle Legend
       Barcode   PDG ID      ( Px,       Py,       Pz,     E ) Stat  DecayVtx

________________________________________________________________________________ GenVertex: -1 ID: 0 (X,cT):0

I: 1         7        21 -5.87e-14, 9.60e-15, 3.41e+01, 3.41e+01 42        -1
O: 1         3        21  0.00e+00, 0.00e+00, 3.41e+01, 3.41e+01 21        -3

GenVertex: -2 ID: 0 (X,cT):0

I: 1         8        21  3.20e-14, 0.00e+00,-7.23e+01, 7.23e+01 41        -2
O: 2         4        21  0.00e+00, 0.00e+00,-1.19e+00, 1.19e+00 21        -3
            11        21  9.42e-01,-1.56e-01,-7.11e+01, 7.11e+01 43       -12