usedir -D: update styles;

--- a/NEWS	Fri Mar 24 13:47:36 2000 +0100
+++ b/NEWS	Fri Mar 24 13:48:01 2000 +0100
@@ -23,6 +23,9 @@
 (isatool document -c); may retain a copy somewhere else via -D option
 of isatool usedir;
 
+* isatool usedir -D now lets isatool latex -o sty update the Isabelle
+style files, achieving self-contained LaTeX sources;
+
 * old-style theories now produce (crude) LaTeX output as well;