Note: not yet complete!

Things to mention:
*: data structures for which condor_submit_dag arguments get passed down, which don't (see dagman_recursive_submit.h)
*: various provisions for this in condor_submit.cpp
*: lazy creation of .condor.sub files for lower-level DAGs
*: nested DAGs and rescue DAGs
*: abort-dag-on: aborts only its own DAG, not the entire workflow