code: def _format_count_file(count_file, data):
      
      COUNT_COLUMN = 5
      out_file = os.path.splitext(count_file)[0] + ".fixed.counts"
      if file_exists(out_file):
          return out_file
  
      df = pd.io.parsers.read_table(count_file, sep="\t", index_col=0, header=1)
      df_sub = df.ix[:, COUNT_COLUMN]
      with file_transaction(data, out_file) as tx_out_file:
          df_sub.to_csv(tx_out_file, sep="\t", index_label="id", header=False)
      return out_file
docs: this cuts the count file produced from featureCounts down to
      a two column file of gene ids and number of reads mapping to
      each gene