presence related changes:

- moved presence status cmd handling from notifier and publisher to
  presence main allowing notifier and publisher coexist
- added handling of out of sync (412) publish reply
- added missing unlinks and derefs
- added dummy_resph function to core in order to avoid crash when
  handling presence related replies after presence module has been
  unloaded
- increased sleep time in hack that tries to postpone unregistering
  until all notifies have been arrived