changed the fixed 6 daughters in GTreeMeson to a TClonesArray of variable length.
There is no more pdg_code in GTreeMeson, cause you can only make a variable 2dim array of Objects. Due to that GTreeMeson is filling all photons first. With NSubPhotons and NSSubChargedPi one can extract a 4vector without testing its mass, the total daughter # and the decay type easily.