Barcode counts for transposon screens

Barcode counts generated from Ion Torrent sequencing data. Barcode (*.bc) files containing raw per-sample read counts for each barcode are combined to form summary files for each sequencing run (sims- and west-summary.tsv). The group.r script (customised for each seqeuncing run) combines counts for barcodes that are close in terms of Levenshtein distance, since such barcodes are likely to be systematic sequencing errors. The gg_col files are the output. Barcodes from the "west" (PB3) end of the transposon are reverse complemented (*.rc) to match with the mapping data.