Mostly consistency updates, plus a couple of minor fixes.
Line breaks in translated control text strings do not work, so have
been removed.
Obsolete ";categories" commands removed, and ";info" commands replaced
with standard Lisp comments.
... Because xgettext will just remove the \, not replace \n with newline.
That's consistent with Lisp reader behavior in this documentation:
http://www.lispworks.com/documentation/lw70/CLHS/Body/02_de.htm
The XLisp reader, which replaces \n with newline, is nonstandard.
So, to accommodate xgettext, use (format nil "...~%...") instead, or where
you can't do that in a $ header line, just make a line break inside the ""
There are a few "\n" left alone in sample-data-export.ny which are neither
in $ lines nor inside (_ "...")