pdb integration

[jesteria]

Should be able to either supply flag –

manage --pdb …

– and/or invoke via module –

python -m pdb -m argcmdr …

(…presuming second form is viable – it might not be).

See also: #1

[jesteria]

Second form might not be viable (for this) because in command line usage, argcmdr raises its own SystemExit, which appears to interrupt post-mortem.

If this is the case, unclear that argcmdr could detect this situation. Instead, might have to be made aware with --pdb flag, (and from that it can know to import pdb on its own).