Prioritize normals.
Prioritize normals.

Generalizes tumor/normal batching to the following three rules:

1) use the highest priority sample as the matched normal if it exists
2) if multiple tumor sample types exist, combine them all together and run
   against the matched normal
3) run the rest of the normals alone as tumors in their own batch

Cyberbio-Lab/bcbio-nextgen,mjafin/bcbio-nextgen,elkingtonmcb/bcbio-nextgen,lbeltrame/bcbio-nextgen,fw1121/bcbio-nextgen,guillermo-carrasco/bcbio-nextgen,chapmanb/bcbio-nextgen,vladsaveliev/bcbio-nextgen,fw1121/bcbio-nextgen,vladsaveliev/bcbio-nextgen,lpantano/bcbio-nextgen,elkingtonmcb/bcbio-nextgen,guillermo-carrasco/bcbio-nextgen,mjafin/bcbio-nextgen,biocyberman/bcbio-nextgen,gifford-lab/bcbio-nextgen,lpantano/bcbio-nextgen,guillermo-carrasco/bcbio-nextgen,lpantano/bcbio-nextgen,verdurin/bcbio-nextgen,Cyberbio-Lab/bcbio-nextgen,fw1121/bcbio-nextgen,gifford-lab/bcbio-nextgen,Cyberbio-Lab/bcbio-nextgen,a113n/bcbio-nextgen,chapmanb/bcbio-nextgen,lbeltrame/bcbio-nextgen,brainstorm/bcbio-nextgen,lbeltrame/bcbio-nextgen,elkingtonmcb/bcbio-nextgen,gifford-lab/bcbio-nextgen,brainstorm/bcbio-nextgen,mjafin/bcbio-nextgen,verdurin/bcbio-nextgen,hjanime/bcbio-nextgen,a113n/bcbio-nextgen,hjanime/bcbio-nextgen,vladsaveliev/bcbio-nextgen,verdurin/bcbio-nextgen,hjanime/bcbio-nextgen,a113n/bcbio-nextgen,chapmanb/bcbio-nextgen,biocyberman/bcbio-nextgen,brainstorm/bcbio-nextgen,biocyberman/bcbio-nextgen