We want to do this to make it as easy as possible to run CWL workflows in Arvados. Adding it to arvados/jobs makes that simple because we already have infrastructure to keep it up-to-date on clusters. * Update the arvados/jobs image to be based on Debian jessie. * Add the cwl-runner package to arvados/jobs. * Add a crunch_script to the Arvados repository to call cwl-runner by filling in inputs from the current job's script_parameters.