Don't crash when a slot is deregistered in the middle of signal processing
Don't crash when a slot is deregistered in the middle of signal processing

this was possible (and used) with FbTk::Subject, but the implemetation of FbTk::Signal didn't
support it, which made it impossible to continue with conversion.

Arkq/fluxbox,lukoko/fluxbox,lukoko/fluxbox,Arkq/fluxbox,luebking/fluxbox,luebking/fluxbox,olivergondza/fluxbox,Arkq/fluxbox,naimdjon/fluxbox,Arkq/fluxbox,luebking/fluxbox,lukoko/fluxbox,luebking/fluxbox,lukoko/fluxbox,naimdjon/fluxbox,olivergondza/fluxbox,lukoko/fluxbox,olivergondza/fluxbox,luebking/fluxbox,naimdjon/fluxbox,olivergondza/fluxbox,naimdjon/fluxbox,naimdjon/fluxbox,Arkq/fluxbox,olivergondza/fluxbox