Several GUI changes/fixes
- several sub windows stays now within main middle window
- after adding ports to or removing ports from service, the service window reloads
	- added edit_service_destroy function
- after adding or removing hosts from group, the group window reload
- rename edit_zone_network title from 'Networks' to 'Network' in top menu (because it's one network)
- added top menu to zones_section_menu_networks with title 'Networks'
  (this was missing and going back from groups, the top menu wasn't updated)
GUI fixes
- Portranges at service can scroll now (and have 'more' text)
- Fixed portranges window size
- Zone (sub)windows did have wrong offset for 'more' text
GUI improvements for 80x24
- function VrWinGetOffset
  - center window if it's higher then main middle window
  - try to show always the top menu
- Edit interface window uses now VrWinGetOffset
- Small improvements/fixes since last change
nflog: add library support for nflog rule

Nflog rule to act in a similar way as nfqueue, so processing each
packet.
vuurmuur_conf: add support for creating nflog

Allow creating the rules and setting the nflog number.
vuurmuur: support new NFLOG rules

Setup these rules like NFQUEUE rules, as after the initial match
we want to keep matching.
minor fixes

Unused variable, use strlcpy instead of strncpy.
Also, in services it would display 'no port ranges' when there were
actually already portranges defined.