Bug 453222

SUMMARY
***
In "feed properties", please add a "filename prefix" field.
***

I read many podcast feeds where each article has an *.mp3 file
as an enclosure.  For those I decide I want to listen to, I
right-click on the enclosure link and do "Save link as ..."
to save the *.mp3 file to disk.

Some feeds have good names for the enclosure files, such
as "feedname-episodeNNN.mp3".

But other feeds use a GUID or some other random string
for filename for every enclosure in the feed.  The enclosures
are named things like "12631FEEDBEEFABCFED8768.mp3".

So, please add a "filename prefix" field to the feed
Properties dialog.  When creating a new feed, the default
value of the field should be the feed name.  The user can
edit the field to empty, or type in any value they wish.

Then every time user does a "Save link as ..." on an
enclosure, the filename sent to the Save As dialog should
be the prefix concatenated with the enclosure filename
from article.  So for example I could set a feed to have a
prefix of "FreshAir-", and when I go to save an enclosure
that the article names as "12631FEEDBEEFABCFED8768.mp3",
the Save As dialog gets suggested name of
"FreshAir-12631FEEDBEEFABCFED8768.mp3".

This will help me organize and listen to saved enclosure
files.  Thanks.