nmbd_elections.c: Added new parameter to dump_workgroups call.

nmbd_elections.c: Added new parameter to dump_workgroups call.
nmbd_incomingdgrams.c: Deal with announcements with servertype == 0 - these
 are announcements that a machine is shutting down and must be treated differently.
nmbd_serverlistdb.c: Exposed remove_server_from_workgroup as external.
  Added code to dump out workgroups on signal correctly.
nmbd_workgroupdb.c: Added new parameter to dump_workgroups call.
Jeremy.
(This used to be commit f7591109b968c66012af5e9fe818bba8e6f1cf23)