Core:
 * debug/test command and response handling
 * out-of-order responses (send to all listeners?, all clients? basic mode?)
 * add listener tables (for requests, responses and other messages)
 * config-parser (config file and improve parser for modules config)
 * improve module loader (allow multiple search paths)
 * finish API for command & response dispatch tables
 * module API clean-up, finalize, freeze

Modules:
 * add modules
   - udp_listen, udp_connect
   - unix_listen, unix_connect
   - token (tokens=files using inotify)
   - PTY
   - FIFO (named pipe)
   - SSL
 * tcp_connect
   - reconnect after connection loss
   - try all resolved remote addressess (also at reconnect)
 * exec
   - add support for parameters and environment variables
   - try to restart child if it exits