Provide a /bin/cat based inline encoding?

[Kai Grossjohann]

I've resisted this for a long time, but it seems that people are
starting to use Tramp with remote systems that aren't really Unix
systems, because they are too far stripped down.

So it would be useful to allow Tramp to interoperate with really dumb
hosts, which have neither Perl nor uuencode, nor mimencode.

And now Tramp uses a lot of random characters in the prompt, so I
guess it should be fairly safe to just use an encoding based on
/bin/cat.

Any volunteers? ;-)

Kai