Add server watchdog and config reload test
New config option: server.config_reload_interval_ms
New config option: 'debug.config'

Logs some information about configuration file loading and re-loading
Fix return value of mdp_send()
mdp_send() and mdp_recv() do not pass zero-length buffer in iovec
Improve "mdp_client.h" layout and comments
New "config sync" command
Improve "mdp ping" command

Packet stats now exclude duplicate pong replies

With <count> arg, exits immediately once a pong has been received for
every ping, unless new --wait-for-duplicates option given

Routing tests for unreliable links now assert all pongs received and
very few duplicates
UNFINISHED MDP filter rules configuration file