[tex-live] tlmgr and command interface

[Karl Berry]

    > 4 - the option --interactive (tlmgr show the list of update items and
    > waiting for a user input);

I think the best way to implement such a thing would be to write a
separate "front end" to tlmgr (like Adam Maxwell's TeX Live Utility for
MacOSX), which makes use of the --machine-readable output we implemented.

The core code shouldn't provide every possible user interface style.
It's already too complex.

karl