Made hiding widgets for guests/registered sensible.

Makes widgets hide-able for registered users or guests.

This is a situation where imo a "group-selector" gui element/code pattern should be used, though. Like I want to set a boolean on/off for some set of groups.... there seems to be a lot of situations where that kind of gui element would be useful (for example, it feels like setting permissions for categories could really use that, no offense to Julian's drop-downs :stuck_out_tongue:). Maybe the element would be like the second one here but with groups -- https://fk.github.io/select2-bootstrap-css/