moved-to and moved-from in status output

Hi stsp,

check this WIP patch out, attached. (I've also appended a wild test script
that runs all sorts of things. Reading its bottom-most output may suffice.)

I'd prefer printing the paths relative to the "current working dir" instead
of relative to the WC root (as this patch does now).

Say there was an
[[[
~/wc$ svn mv x/alpha a/b/beta
]]]

currently:
[[[
~/wc$ cd a/b/
~/wc/a/b$ svn st
A + beta
> moved from x/alpha
]]]
(relative to WC_ROOT)

rather:
[[[
~/wc/a/b$ svn st
A + beta
> moved from ../../x/alpha
]]]

but I haven't figured out whether there's code that does this already. And,
to that end, I think those batons should rather pass abspaths (see comments
in the code).

What do you say?

~Neels