Worked on making the assistant able to merge in existing encrypted
git repositories from rsync.net.

This had two parts. First, making the webapp UI where you click to enable a
known special remote work with these encrypted repos. Secondly, handling
the case where a user knows they have an encrypted repository on rsync.net,
so enters in its hostname and path, but git-annex doesn't know about that
special remote. The second case is important, for example, when the
encrypted repository is a backup and you're restoring from it. It wouldn't
do for the assistant, in that case, to make a *new* encrypted repo and
push it over top of your backup!

Handling that was a neat trick. It has to do quite a lot of probing, including
downloading the whole encrypted git repo so it can decrypt it and merge it,
to find out about the special remote configuration used for it. This all
works with just 2 ssh connections, and only 1 ssh password prompt max.

Next, on to generalizing this rsync.net specific code to work with
arbitrary ssh servers!

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Today's work was made possible by [RMS's vision 30 years ago](http://article.olduse.net/771@mit-eddie.UUCP).
