autoanswer: squashed logging + argparse wrappers

[mk-fg]

Squashed following intermingled changes:

• Use argparse for cli invocation, overridable Defaults, make stuff like raven optional (but opt-out).
• Use logging instead of print statements.
• Don't prompt for Enter, stop on ^C.
• Use one err_report_wrapper decorator for all places where non-critical exception handling and logging would be necessary.

Applied these top-to-bottom, looks like more work to unsquash these for small script than it'd be worth it.