Added git-remote-p2p-annex, which allows git pull and push to P2P networks
provided by external commands.
This is a refactor of git-remote-tor-annex, and should just work. Except
possibly for quirks with the address parsing. I've checked that the address
parsing basically works.
One thing I don't understand is why git-remote-tor-annex removes "/*" from
the end of the address. The git history does not provide any hints. So I
didn't make git-remote-p2p-annex do the same. Maybe that is needed in some
situation? But, a P2P address could contain "/", so removing it would be a
problem. I can't see anything in gitremote-helpers(7) about why the url
might get such a thing added to the end of it. My guess is that is not
needed for tor either (but does no harm there since onion addresses never
contain "/").
At this point, the implementation of generic P2P transports needs only
remotedaemon support.
Make programPath never return "git-remote-annex" or other known multi-call
program names, which are not git-annex and won't behave like it.
If the git-annex binary gets installed under some entirely other name,
it will still return it.
This change exposed that readProgramFile actually could crash,
which happened before only if getExecutablePath was not absolute
and there was no ~/.config/git-annex/program. So fixed that to catch
exception.
