Q&A: control codes

Attached is my proposal for Q&A on C0 Characters.

It actually wasn't the topic I intended, but the question came up and I
thought it would be quick and I might do a second one. But it ended up taking
much more time than I thought.

Anyway, for discussion at the next telecon.

Feel free to email constructive comments before then.

Thanks to Francois for the initial pointers.

tex