defensive defaults for more robust experience for new users;

--- a/src/Pure/System/isabelle_process.ML	Fri Nov 12 17:44:03 2010 +0100
+++ b/src/Pure/System/isabelle_process.ML	Fri Nov 12 21:37:01 2010 +0100
@@ -168,7 +168,8 @@
     val _ = OS.Process.sleep (seconds 0.5);  (*yield to raw ML toplevel*)
     val _ = Output.raw_stdout Symbol.STX;
 
-    val _ = quick_and_dirty := true;  (* FIXME !? *)
+    val _ = quick_and_dirty := false;
+    val _ = Goal.parallel_proofs := 0;
     val _ = Context.set_thread_data NONE;
     val _ = Unsynchronized.change print_mode
       (fold (update op =) [isabelle_processN, Keyword.keyword_statusN, Pretty.symbolicN]);