no longer support "isabelle_font" or "symbols";

--- a/src/Pure/Interface/isamode.ML	Fri Nov 09 00:14:17 2001 +0100
+++ b/src/Pure/Interface/isamode.ML	Fri Nov 09 00:15:35 2001 +0100
@@ -55,8 +55,7 @@
 (** run-time initialization **)
 
 fun init isamode =
-  if isamode then print_mode := [Symbol.isabelle_fontN, Symbol.symbolsN, isamodeN]
-  else print_mode := [Symbol.isabelle_fontN, Symbol.symbolsN];
+  if isamode then print_mode := isamodeN :: ! print_mode else ();
 
 
 end;