display-drafts now uses pdf!

--- a/src/Pure/Isar/isar_cmd.ML	Fri Oct 01 11:53:31 2004 +0200
+++ b/src/Pure/Isar/isar_cmd.ML	Fri Oct 01 11:53:50 2004 +0200
@@ -183,7 +183,7 @@
 (* present draft files *)
 
 fun display_drafts files = Toplevel.imperative (fn () =>
-  let val outfile = File.quote_sysify_path (Present.drafts "dvi" files)
+  let val outfile = File.quote_sysify_path (Present.drafts "pdf" files)
   in system ("\"$ISATOOL\" display -c " ^ outfile ^ " &"); () end);
 
 fun print_drafts files = Toplevel.imperative (fn () =>