Make tx2gene to be CSV format.
Make tx2gene to be CSV format.

Thanks to @lpantano for finding this bug.

a113n/bcbio-nextgen,a113n/bcbio-nextgen,biocyberman/bcbio-nextgen,chapmanb/bcbio-nextgen,biocyberman/bcbio-nextgen,a113n/bcbio-nextgen,biocyberman/bcbio-nextgen,chapmanb/bcbio-nextgen,vladsaveliev/bcbio-nextgen,lbeltrame/bcbio-nextgen,vladsaveliev/bcbio-nextgen,vladsaveliev/bcbio-nextgen,lbeltrame/bcbio-nextgen,chapmanb/bcbio-nextgen,lbeltrame/bcbio-nextgen