Index sailfish in parallel.
Index sailfish in parallel.

Closes #1130. Thanks to @parlar.

a113n/bcbio-nextgen,gifford-lab/bcbio-nextgen,chapmanb/bcbio-nextgen,brainstorm/bcbio-nextgen,lbeltrame/bcbio-nextgen,Cyberbio-Lab/bcbio-nextgen,lpantano/bcbio-nextgen,lbeltrame/bcbio-nextgen,chapmanb/bcbio-nextgen,mjafin/bcbio-nextgen,brainstorm/bcbio-nextgen,vladsaveliev/bcbio-nextgen,vladsaveliev/bcbio-nextgen,mjafin/bcbio-nextgen,a113n/bcbio-nextgen,mjafin/bcbio-nextgen,a113n/bcbio-nextgen,lbeltrame/bcbio-nextgen,biocyberman/bcbio-nextgen,vladsaveliev/bcbio-nextgen,biocyberman/bcbio-nextgen,lpantano/bcbio-nextgen,gifford-lab/bcbio-nextgen,biocyberman/bcbio-nextgen,chapmanb/bcbio-nextgen,Cyberbio-Lab/bcbio-nextgen,gifford-lab/bcbio-nextgen,Cyberbio-Lab/bcbio-nextgen,lpantano/bcbio-nextgen,brainstorm/bcbio-nextgen