prefer scala.Console with its support for thread-local redirection;

--- a/src/Pure/General/output.scala	Fri May 02 19:51:40 2014 +0200
+++ b/src/Pure/General/output.scala	Fri May 02 20:01:45 2014 +0200
@@ -12,8 +12,8 @@
   def warning_text(msg: String): String = cat_lines(split_lines(msg).map("### " + _))
   def error_text(msg: String): String = cat_lines(split_lines(msg).map("*** " + _))
 
-  def writeln(msg: String) { System.err.println(msg) }
-  def warning(msg: String) { System.err.println(warning_text(msg)) }
-  def error_message(msg: String) { System.err.println(error_text(msg)) }
+  def writeln(msg: String) { Console.err.println(msg) }
+  def warning(msg: String) { Console.err.println(warning_text(msg)) }
+  def error_message(msg: String) { Console.err.println(error_text(msg)) }
 }
 

--- a/src/Pure/System/isabelle_process.scala	Fri May 02 19:51:40 2014 +0200
+++ b/src/Pure/System/isabelle_process.scala	Fri May 02 20:01:45 2014 +0200
@@ -12,7 +12,7 @@
 
 
 class Isabelle_Process(
-  receiver: Prover.Message => Unit = System.out.println(_),
+  receiver: Prover.Message => Unit = Console.println(_),
   prover_args: List[String] = Nil)
 {
   /* text and tree data */

--- a/src/Pure/System/options.scala	Fri May 02 19:51:40 2014 +0200
+++ b/src/Pure/System/options.scala	Fri May 02 20:01:45 2014 +0200
@@ -147,13 +147,13 @@
           val options = (Options.init() /: more_options)(_ + _)
 
           if (get_option != "")
-            System.out.println(options.check_name(get_option).value)
+            Console.println(options.check_name(get_option).value)
 
           if (export_file != "")
             File.write(Path.explode(export_file), YXML.string_of_body(options.encode))
 
           if (get_option == "" && export_file == "")
-            System.out.println(options.print)
+            Console.println(options.print)
 
         case _ => error("Bad arguments:\n" + cat_lines(args))
       }

--- a/src/Pure/Tools/build.scala	Fri May 02 19:51:40 2014 +0200
+++ b/src/Pure/Tools/build.scala	Fri May 02 20:01:45 2014 +0200
@@ -32,7 +32,7 @@
 
   class Console_Progress(verbose: Boolean) extends Progress
   {
-    override def echo(msg: String) { System.out.println(msg) }
+    override def echo(msg: String) { Console.println(msg) }
     override def theory(session: String, theory: String): Unit =
       if (verbose) echo(session + ": theory " + theory)
 

--- a/src/Pure/Tools/doc.scala	Fri May 02 19:51:40 2014 +0200
+++ b/src/Pure/Tools/doc.scala	Fri May 02 20:01:45 2014 +0200
@@ -77,7 +77,7 @@
 
   def view(path: Path)
   {
-    if (path.is_file) System.out.println(Library.trim_line(File.read(path)))
+    if (path.is_file) Console.println(Library.trim_line(File.read(path)))
     else {
       val pdf = path.ext("pdf")
       if (pdf.is_file) Isabelle_System.pdf_viewer(pdf)
@@ -92,7 +92,7 @@
   {
     Command_Line.tool0 {
       val entries = contents()
-      if (args.isEmpty) System.out.println(cat_lines(contents_lines().map(_._2)))
+      if (args.isEmpty) Console.println(cat_lines(contents_lines().map(_._2)))
       else {
         args.foreach(arg =>
           entries.collectFirst { case Doc(name, _, path) if arg == name => path } match {