WIP: refactor MCTruth to record secondary track

The decay of secondary track is recorded:

 620d570+78         +211           +1           +0 +1.000000e+00 +0.000000e+00 +1.395700e-01 +0.000000e+00 +0.000000e+00 +0.000000e+00  +4.481357e+01 -1.734107e+02 +1.910248e+03
 +6.032941e-03 +3.548164e-01 +3.017565e-01  -0.000000e+00 +0.000000e+00 +0.000000e+00  +0.000000e+00 +0.000000e+00 +0.000000e+00            +0 +0
      parents :  620d570+53
      daughters :  620d570+143

 620d570+143         +211           +0  +1073741824 +1.000000e+00 +1.031763e+01 +1.395701e+02 +4.481357e+01 -1.734107e+02 +1.910248e+03  +3.832479e+01 +1.045657e+02 +1.896184e+03
  -1.457057e-01 +3.747023e-01 -2.205352e-03  +0.000000e+00 +0.000000e+00 -0.000000e+00  +0.000000e+00 +0.000000e+00 +0.000000e+00            +0 +0
      parents :  620d570+78
      daughters :  620d570+144

 620d570+144         +211           +0  +1275068416 +1.000000e+00 +1.132841e+01 +1.395701e+02 +3.832479e+01 +1.045657e+02 +1.896184e+03  -5.469888e+00 +1.777160e+02 +1.915421e+03
  -1.835741e-01 +1.332844e-01 +1.168625e-02  -0.000000e+00 +0.000000e+00 -0.000000e+00  +0.000000e+00 +0.000000e+00 +0.000000e+00            +0 +0
      parents :  620d570+143
      daughters :  620d570+145  620d570+146
 620d570+145          +14           +0  +1073741824 +0.000000e+00 +1.653372e+02 +0.000000e+00 -5.469888e+00 +1.777160e+02 +1.915421e+03  +1.097619e+03 -1.221860e+03 -8.000000e+03
  +3.262080e-03 -4.138860e-03 -2.932212e-02  +3.262080e-03 -4.138860e-03 -2.932212e-02  +0.000000e+00 +0.000000e+00 +0.000000e+00            +0 +0
      parents :  620d570+144
      daughters :
 620d570+146          -13           +0  +1275068416 +1.000000e+00 +1.653372e+02 +1.056584e+02 -5.469888e+00 +1.777160e+02 +1.915421e+03  -5.493795e+00 +1.777447e+02 +1.915641e+03
  -3.262080e-03 +4.138860e-03 +2.932212e-02  -0.000000e+00 +0.000000e+00 +0.000000e+00  +0.000000e+00 +0.000000e+00 +0.000000e+00            +0 +0
      parents :  620d570+144
      daughters :  620d570+147  620d570+148  620d570+149
 620d570+147          -14           +0  +1073741824 +0.000000e+00 +8.727150e+02 +0.000000e+00 -5.493795e+00 +1.777447e+02 +1.915641e+03  -1.830000e+03 -3.273397e+02 +2.327730e+03
  -4.572164e-02 -1.265728e-02 +1.032686e-02  -4.572164e-02 -1.265728e-02 +1.032686e-02  +0.000000e+00 +0.000000e+00 +0.000000e+00            +0 +0
      parents :  620d570+146
      daughters :
 620d570+148          +12           +0  +1073741824 +0.000000e+00 +8.727150e+02 +0.000000e+00 -5.493795e+00 +1.777447e+02 +1.915641e+03  +1.830000e+03 +8.715307e+02 +1.739666e+03
  +4.528590e-02 +1.711731e-02 -4.341702e-03  +4.528590e-02 +1.711731e-02 -4.341702e-03  +0.000000e+00 +0.000000e+00 +0.000000e+00            +0 +0
      parents :  620d570+146
      daughters :
 620d570+149          -11           +0  +1073741824 +1.000000e+00 +8.727150e+02 +5.109989e-01 -5.493795e+00 +1.777447e+02 +1.915641e+03  -4.839841e+00 +1.778084e+02 +1.913533e+03
  +4.645633e-04 -4.755090e-03 -6.381104e-03  -0.000000e+00 -0.000000e+00 -0.000000e+00  +0.000000e+00 +0.000000e+00 +0.000000e+00            +0 +0
      parents :  620d570+146
      daughters :

changed the description

mentioned in commit 64abb61f

merged