mod_post_msg: Add sendxmpp-curl I wrote this script around the same time as this module. My local copy has a last modification timestamp of 2011-03-29, so it's been unchanged since then. The original rationale was that it seemed overkill to establish an entire XMPP session just to send a single message. Nowadays I'm quite happy using `clix` for this kind task.

This module writes out a traceback to `traceback.txt` in Prosodys data
directory (see `prosodyctl about`) when the signal `SIGUSR1` is
received. This is useful when debugging seemingly frozen instances in
case it is stuck in Lua code.