Unclear `--debug` argument to StructuralCompare

[jgoeders]

In utils/structural.py:

parser.add_argument("--debug", help="Utilize debugging functionality")

It's unclear what format this is. Should this have a action="store_true"?

In structural/structural.py there is this:

"debug": "--debug True" if self.debug else "",

which suggests it is just a boolean flag. This should be clean up.