[dev] Scry restricting comments

[Duck]

> > Come to think of it, what do folks think of doing things like this with a
> > permission? Could be even more flexible then...
>
> Should be logically the next step.

I practice, I think, that we will fall in a general situation that the 
authenticated users can write comments and all the other can read it.

Another thing gets me. The rendering of the commens is often the same for all 
the modules on a site. And is different for every singe site. So maybe would 
be good to pass the comments rendering trough an Agora template of better 
trough a Hook, to allow transparent upgrading of multiple sites.

Duck