[imp] Spam plug-in

[Otto Stolz]

Hello Matej Baćo,

you wrote:
> 1. While the person is reading mail he can flag it as SPAM which will 
> contact the remote service, register content of mail as SPAM and 
> delete the message or put it in SPAM folder. 

This is in Imp available, already; cf. the  “Administration” → “Setup”
→ “Mail (imp) H3” → “Message and Spam”, and “Options” → “Mail” →
“Deleting and Moving Messages”, menus (the contents of the latter
can be influenced via the horde/imp/config/prefs.php file via the
'delete_spam_after_report' and 'empty_spam_menu' options).

> 2. When the person checks new mail, list should be check for SPAM by 
> contacting remote service and deleting all SPAM mail or moving it to 
> SPAM folder. 

This is already available in Ingo, I reckon. (We are not using
Ingo, but rather a home-brewn Sieve solution.)  A Sieve script
(one of the available Ingo backends) has the advantage, that
the messages are deleted, or moved, when the arrive in the inbox,
rather than at fetching time; hence, the user never needs to wait
for the decision to be made, and the scheme works equally for any
mail-client, not only for Imp.

Best wishes,
   Otto Stolz