shuffled genparticles relationships

[cp3-support]

It seems that when using hepmc input, the output particles in the intermediate stage lose their proper relationships. For instance:

root [1] GEN->Scan("Particle.Status:Particle.PID:Particle.D1:Particle.D2:Particle.M1:Particle.M2")
***********************************************************************************************
*    Row   * Instance * Particle. * Particle. * Particle. * Particle. * Particle. * Particle. *
***********************************************************************************************
*        0 *        0 *         3 *      2212 *         3 *        22 *         0 *         0 *
*        0 *        1 *         3 *      2212 *         4 *        91 *         0 *         0 *
*        0 *        2 *         3 *         1 *         5 *        32 *         1 *         1 *
*        0 *        3 *         3 *         2 *         6 *        90 *         2 *         2 *
*        0 *        4 *         3 *        -1 *         9 *         7 *         3 *         3 *
*        0 *        5 *         3 *         2 *         9 *         7 *         4 *         4 *
*        0 *        6 *         3 *   1000024 *        11 *         8 *         5 *         6 *
*        0 *        7 *         2 *   1000024 *         0 *         0 *         7 *         7 *
*        0 *        8 *         3 *   1000022 *        10 *        10 *         5 *         6 *
*        0 *        9 *         1 *   1000022 *         0 *         0 *         9 *         9 *
*        0 *       10 *         3 *   1000022 *        12 *        12 *         7 *         7 *
*        0 *       11 *         1 *   1000022 *         0 *         0 *        11 *        11 *
*        0 *       12 *         3 *        16 *        14 *        14 *         7 *         7 *
*        0 *       13 *         1 *        16 *         0 *         0 *        13 *        13 *
*        0 *       14 *         3 *       -15 *        16 *        16 *         7 *         7 *
*        0 *       15 *         2 *       -15 *        17 *        19 *        15 *        15 *
*        0 *       16 *         1 *        12 *         0 *         0 *        16 *        16 *
*        0 *       17 *         1 *       -11 *         0 *         0 *        16 *        16 *
*        0 *       18 *         1 *       -16 *         0 *         0 *        16 *        16 *
*        0 *       19 *         2 *         1 *        23 *        23 *         3 *         3 *
*        0 *       20 *         2 *        21 *        23 *        23 *         3 *         3 *
*        0 *       21 *         2 *      2203 *        23 *        23 *         1 *         1 *
*        0 *       22 *         2 *        92 *       137 *       150 *        20 *        22 *
*        0 *       23 *         1 *      -211 *         0 *         0 *        23 *        23 *

[cp3-support]

A bugfix was written by Nadja Strobbe (thanks !). It will be tested and included in the next bugfix release which should include the hepmc 2.06 compatibility too.