This function does the same thing as KVSAVE, but also sets the mass of track ISAVE to the mass of `part-name'. As in KVSAVE, the original track ITK is not changed. For charged tracks, KIDSAV will save tracks as the appropriate particle or antiparticle depending on their charge. For example KIDSAV(ITK, `K+') will save positive tracks as K+ and negative tracks as K-.