r5276: - added support for NBT_OPCODE_REFRESH2 (type 0x9)

r5276: - added support for NBT_OPCODE_REFRESH2 (type 0x9)

- when registering with a WINS server, initially use multi-homed
  registration, then switch to name refresh requests. Send refresh
  requests only to the WINS server that responded to our
  registration. If that server goes away, then start the registration
  from scratch. This makes registration more robust to WINS server
  failure.

- send WINS registration requests out on our first interface rather
  than an unbound interface, to avoid the problem of WACK replies
  being sent to the wrong port (w2k3 WINS server does this)