DAGassist               Generate a (console/LaTeX/word/excel/txt)
                        report classifying nodes and comparing models
bad_controls_in         flag bad controls (mediator/collider/desc of Y)
                        among a candidate set
classify_nodes          Classify DAG nodes
print.DAGassist_report
                        Print method for DAGassist reports
print.DAGassist_roles   Print node classifications (aligned)
print.DAGassist_validation
                        Minimal, clean printout for validation results
                        with color coding
