Additional options for Gamma Conversion Split Sim and Redecay modes

Options to turn the SplitSim feature on in Gauss to allow more efficient simulation of gamma conversion filtered samples. Also includes a 1000 redecay options file to counteract the low gamma conversion efficiencies. To get it ready as quick as possible, also includes an options to redecay everything with at least the flavour of the signal on (will be released in next Gauss versions)