Optionally, check and report if inferred paths (still) exist

[xandkar]

If we find path /foo/bar (host's conflicted copy 1931-12-17).txt, we infer that the original path must've been /foo/bar.txt, and report tree:

/foo/bar.txt
        /foo/bar (host's conflicted copy 1931-12-17).txt

But, this does not necessarily mean that /foo/bar.txt exists! So, we should probably have an option to check paths' existence and report it with a status prefix, maybe something along these lines:

NOT_FOUND | /foo/bar.txt
        FOUND | /foo/bar (host's conflicted copy 1931-12-17).txt