Cleanups to prepare this code for wider use (likely merged into hostapd):
o add (required) cmd line args to specify the set of ifnet's to monitor

for WDS discovery msgs; "any" is a wildcard

o change the default script run on wds vap create to the "null script"
o auto-daemonize; add -f option to force foreground operation
o add -P option for integration with rc.d (implementation missing, tba)
o use syslog; default to log up to LOG_INFO, -t (terse) gives you up to

LOG_ERR, and -v (verbose) gives you up to LOG_DEBUG

o scan for existing vaps on startup to recover existing state
o correct some types