Print GOEA results to text file.

def wr_txt(self, fout_txt, goea_results, prtfmt=None, **kws):
        """Print GOEA results to text file."""
        if not goea_results:
            sys.stdout.write("      0 GOEA results. NOT WRITING {FOUT}\n".format(FOUT=fout_txt))
            return
        with open(fout_txt, 'w') as prt:
            if 'title' in kws:
                prt.write("{TITLE}\n".format(TITLE=kws['title']))
            data_nts = self.prt_txt(prt, goea_results, prtfmt, **kws)
            log = self.log if self.log is not None else sys.stdout
            log.write("  {N:>5} GOEA results for {CUR:5} study items. WROTE: {F}\n".format(
                N=len(data_nts),
                CUR=len(MgrNtGOEAs(goea_results).get_study_items()),
                F=fout_txt))