cli: undo the effects of [http://allmydata.org/trac/tahoe/changeset/20081222235453...

cli: undo the effects of [http://allmydata.org/trac/tahoe/changeset/20081222235453-92b7f-f841e18afb94e1fd95e6dafb799a3d876dd85c69]
We're just going to mark unicode in the cli as unsupported for tahoe-lafs-1.3.0.  Unicode filenames on the command-line do actually work for some platforms and probably only if the platform encoding is utf-8, but I'm not sure, and in any case for it to be marked as "supported" it would have to work on all platforms, be thoroughly tested, and also we would have to understand why it worked.  :-)