fix candidate generation bug and add crude outlier filter
fix candidate generation bug and add crude outlier filter

simpsonlab/nanopolish,rmp/nanopolish,jts/nanopolish,simpsonlab/nanopolish,mateidavid/nanopolish,mateidavid/nanopolish,jts/nanopolish,simpsonlab/nanopolish,rmp/nanopolish,rmp/nanopolish,rmp/nanopolish,jts/nanopolish,mateidavid/nanopolish,mateidavid/nanopolish,simpsonlab/nanopolish,mateidavid/nanopolish,jts/nanopolish,jts/nanopolish