bugfixing/minor updated

one wire:
* script/code linked to device will be executed when device changes its
status (online/offline). $params['STATUS_CHANGED'] can be used to handle
this event
* bug fixed with removing linked object.property

hosts online:
* added ability to set linked object.property with host's status (0/1)

save / restore
* fixed bug with manual database backup

webvars
* fixed bug with setting script execution