proper install_fonts;

--- a/src/Tools/Graphview/src/frame.scala	Tue Sep 25 22:52:40 2012 +0200
+++ b/src/Tools/Graphview/src/frame.scala	Wed Sep 26 14:13:07 2012 +0200
@@ -23,6 +23,7 @@
       try {
         Platform.init_laf()
         Isabelle_System.init()
+        Isabelle_System.install_fonts()
 
         args.toList match {
           case List(arg) =>