wrong Tn5 shifting.

[ruochiz]

The Tn5 shifting in this repo has been using

awk -v OFS="\t" '{if($9=="+"){print $1,$2+4,$6+4,$7}else if($9=="-"){print $1,$2-5,$6-5,$7}}'

But it should be

awk -v OFS="\t" '{if($9=="+"){print $1,$2+4,$6-5,$7}else if($9=="-"){print $1,$2-5,$6+4,$7}}'

(For paired-end sequencing, if the first mate mapped to '+', shift +4 on the left cut site, and shift -5 on the right cut site (which is on the other read mapped to '-',)

With the current code, the Tn5 shifting has been using +4/+4 shifting for most of the reads.