Add a profanity-flag to filtered objects

[MartinKoerner]

Hi there,

I want to suggest a flag for filtered content, so that I can create a list for the admin with all filtered objects. As far as I can see, the only possibility for now is to monkey-patch setup_callbacks_for.
For my purpose, it would be great to have a non-destructive version, but checks for profanity while update and set the "dirty"-flag, if it found some.