summarise_popDemographics function

This function will use output from summarise_experimentFiles and summarise_experimentParameters to help with expectations concerning run output and handling. This will save an RData file which will contain one object: all_popSets, which is a list of relevant control information about I/O and then a series of other RData files which contain the demographics information as a matrix with the mean and standard deviation of demographics for all replicates.