minor cleanup... all that's left to do is

minor cleanup...  all that's left to do is
* make headers and footers for both the POD and SGML content
* make an SGML generator
* finish the command-line handling

Also, some of the documentation in usage.h will have to
be adjusted.  expr needs some lines to be indented, and
ls has a stray comma.  I may have missed some things...
but it looks OK for the most part.