Instead of having a dumb readreply, already drop some of the unneeded
lines of the command when sending the request, and handle errors in
place.
This simplifies the code a little, even though it requires a few more
"discard loops" in the code (to avoid garbage in Asterisk's logs).
This is a bit trickier, since the voicemail might not be enabled
anywhere. Unfortunately it's not easy to set this up during
autoconfig, as voicemails can be added on the fly.
This plugin is targeting to enter main distribution in 2.1 to remove
the multiple Asterisk plugins present in 2.0.
It features full autoconfiguration support, multigraph capabilities,
and less error-prone code.
For the moment, it only implements a replacement for asterisk_channels.
