Extend libsdp(3) API to allow service registration and removal.
Fix uninitialized variable bug in sdpcontrol(8).
Reviewed by: imp (mentor)
No objection: ru
(aka RFC2292bis). Though I believe this commit doesn't break
backward compatibility againt existing binaries, it breaks
backward compatibility of API.
Now, the applications which use Advanced Sockets API such as
telnet, ping6, mld6query and traceroute6 use RFC3542 API.
Obtained from: KAME
