edit samtools sort command to work for samtools 1.3.1
edit samtools sort command to work for samtools 1.3.1

hdashnow/STRetch-paper,hdashnow/STRetch-paper,Oshlack/STRetch,Oshlack/STRetch,hdashnow/STRetch-paper,hdashnow/STRetch,Oshlack/STRetch,hdashnow/STRetch