calcTrep function

A function to calculate Trep values from a sync-seq experiment calcTrep function fits a Boltzman sigmoid function into relative copy number datapoints for every genomic bin of the provided sync-seq merged dataframe. It then extracts time at which half of the cells have this genomic bin replicated (Trep). The output of the function is a dataframe containing Trep and TrepErr data for every genomic bin in a BED-like format.