Reopen the sharetab just in case it have been changed
(such as libshare would do) in is_shared().
The option sharesmb should not be inherited by childs.
Samba is perfectly able to show child file systems...
* Use REGISTRY SHARES instead of USER SHARES - more confiurable.
* On some machines, there is a "global" share. This isn't really a share,
  but the possibility to modify global options. So first get a line of
  _real_ shares using 'net conf listshares' and _then_ cyckle through
  them retrieving info with 'net conf showshare <share>'.