2. Remote instantiation for proxies. (done)
+2. Bug: In a repo cloned with ssh from a proxy repo,
+ running `git-annex init` sets annex-uuid for the instantiated remotes.
+ This prevents them being used, because instanatiation is not done
+ when there's any config set for a remote.
+
3. Implement proxying in git-annex-shell.
+ (Partly done, still need it for GET, PUT, CONNECT, and NOTIFYCHANGES
+ messages.)
4. Either implement proxying for local path remotes, or prevent
listProxied from operating on them.
+4. Either implement proxying for tor-annex remotes, or prevent
+ listProxied from operating on them.
+
4. Let `storeKey` return a list of UUIDs where content was stored,
and make proxies accept uploads directed at them, rather than a specific
instantiated remote, and fan out the upload to whatever nodes behind