make_register           Register objects to be returned from
                        'make_with_source'
make_with_dir           Create a pipeline using roxygen tags
make_with_recipe        Make targets out of dependencies using a recipe
make_with_source        Make targets out of dependencies using a source
                        file
out_of_date             Check if targets are out-of-date vis-a-vis
                        their dependencies
pipeline-accessors      Access and interface with Pipeline.
pipeline-vis            Visualise the Pipeline.
