copperbox updates

Updates to Copperbox...

Revision 2730 - added zformat, formatting combinators with an interface like pretty print combinators but no prettiness i.e. no fitting / line breaking.

Revision 2731 - added directory-script. This should replace directory-diff, however I'm not sure if I have a use-case to work on this project any more, so it might get punted to the long grass as it currently stands.

Revisions 2732 & 2733 - renaming hpj-pretty-expr to pretty-expr-hpj and reorganizing the source directories.

I've done quite a bit of work over the last fortnight, but I haven't felt like committing it until today. I had a processor meltdown this morning (the fan on the processor needs the contact "glue" re-applying) so I thought I better finally make a commit.