CWL: update documentation, include sample tarball
CWL: update documentation, include sample tarball

Document latest improvements for variant calling and improve running
and generating documentation to make CWL bcbio easier to test with a
self-contained download.

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