Put the log and scratch text in the same window.

This is a step towards Ticket #40360 without going all the way.  You can
open additional viewer windows.  They are not connected by an
Oberon-style messaging system (yet.  It would be nice to use the Tk event
system for that.)

This way the log and the main/scratch/system-menu text are conceptually
unified in the (equivelent of "desktop") base metaphor of the system.

joy/gui/textwidget.py

@@ -426,7 +426,6 @@ class TextViewerWidget(tk.Text, MouseBindingsMixin, SavingMixin):
 		return 'break'
 
 	def init(self, title, filename, repo_relative_filename, repo, font):
-		self.set_window_title(title)
 		if os.path.exists(filename):
 			with open(filename) as f:
 				data = f.read()
@@ -434,7 +433,6 @@ class TextViewerWidget(tk.Text, MouseBindingsMixin, SavingMixin):
 			# Prevent this from triggering a git commit.
 			self.update()
 			self._cancelSave()
-		self.pack(expand=True, fill=tk.BOTH)
 		self.filename = filename
 		self.repo_relative_filename = repo_relative_filename
 		self.repo = repo
@@ -472,3 +470,15 @@ class TextViewerWidget(tk.Text, MouseBindingsMixin, SavingMixin):
 
 		T.pack(expand=1, fill=tk.BOTH)
 		T.see(tk.END)
+
+
+def make_main_window(world):
+	m = tk.PanedWindow(orient=tk.HORIZONTAL)
+	m.winfo_toplevel().title('Thun')
+	m.pack(fill=tk.BOTH, expand=True)
+	H = 45
+	t = TextViewerWidget(world, m, width=128, height=H)
+	log = TextViewerWidget(world, m, width=73, height=H)
+	m.add(log)
+	m.add(t)
+	return m, t, log