* _cfgimpl_ => _impl_
* optimpl_ => impl_
* properties/permissives are now set/frozenset
* validation raise ValueError if not valid, didn't return anything otherwise
* consistencies are now validate in setting and when deleting value
* ip/network with netmask consistency now works
* DomainnameOption now works
* if no validation, don't set cache for value
* symlinkoption: remove path (not used)
