New snapshot: RSS import, bug fixes

[Dmitry Borodaenko]

Hi Boud and lurkers!

First of all, apologies for taking so long to get this update out the
door. With the amount of time I can dedicate to Samizdat, I can barely
keep up with Boud's posts and patches, integrating them takes even
longer.

Still, I managed to rework the RSS import patch so that I can
integrate it, and apply the most obvious fixes for several bugs:

#19830 - upload file message changed to clarify the purpose of this
option; I've updated Belarusian and Russian translations, others need
to be updated accordingly

#20303 - "cut the knot" kind of solution applied: the whole option,
and a couple of others, are made available in basic interface;
eventually, I'd like to get rid of the basic/advanced interface split,
advanced interface is only there because some parts of Samizdat UI are
more complicated than they should be

#20305 - obvious fix for an obvious bug, made even easier by the
refactoring applied for the previous bug

#20678 - it looks like the the whole idea of redirecting back to where
login is initiated from is too complex to be implemented without bugs
or kludges; since it's not tremendously useful, I removed it for now,
this will make this bug go away

#20491 - the real cause of this bug was that CSRF protection code
didn't handle the case when form action is different from the location
where form is displayed, this is now fixed

RSS import is configured pretty much the same as in Boud's patch, but
it works quite differently: feeds are fetched and parsed by an
external script (bin/samizdat-import-feeds) that can be placed in
crontab on an arbitrary schedule (remember though that fetching feeds
more often than hourly is not polite). The script puts the results
into the DRb cache as persistent entries available across all sites,
so that two sites importing the same feed will only fetch it once. The
script fetches maximum number of entries, it is up to each site to cut
these entries down to the limit configured for given site.

Boud, please let me know if you can and want to update doc/install.txt
with the above instructions explained in a more user-friendly manner,
otherwise I'll try to do it myself.

-- 
Dmitry Borodaenko