We don't guess the current profile anymore if the value of the profile === -1
Also sets $this->scoped for all ScopingNoticeStream inheritors, which just
like in an Action can be null if we're not scoped in any way (logged in).
Now we have to fix any code in the core which directly uses the Fave class
or any other favorite stuff, since it is pluginised and thus might not be
available on some installations.
