Initial basic version for a 'multitool' console test battery.
For now, it implements a simple sniffer (with output similar
to ipaaca-iu-sniffer).
Planned: switching mode (sniffer, injector, modifier ...)
per command-line or interactively with keys; also implement
other language versions.

Caveat for sniffer function: resend_requests trigger ADDED event
twice (once for the sniffer "" scope, once for the hidden one).