Smarter nnfolder behavior requested

[Mats.Lidell@eua.ericsson.se (Mats Lidell)]

Hi,

It seems like all the nnfolders are loaded into emacs even though I
don't think they need to. Couldn't ding be a bit smarter here. Things
to consider:

 * After noticing that there are no articles to read (that is a normal
   case) then it could just kill the buffer freeing some memory: 

 * Keeping information like: if the nnfolder file is older then newsrc
   then nothing new has happened so no need visiting that folder.

 * Visit the folder on entry. That is visit it twice: one time when
   building the group-buffer and another time when entering the group.

Is there any other way to achieve this with the current
implementation. I like to have a lot of mail folders available
together with the local news feed but dislike the fact that it makes
my emacs really big.

%% Mats