Initial bring over of VUI code. (Won't work yet.)

joy/vui/debug_main.py

@@ -0,0 +1,18 @@
+import sys, traceback
+
+# To enable "hot" reloading in the IDLE shell.
+for name in 'core main display viewer text_viewer stack_viewer persist_task'.split():
+    try:
+        del sys.modules[name]
+    except KeyError:
+        pass
+
+import main
+
+try:
+    A = A # (screen, clock, pt), three things that we DON'T want to recreate
+          # each time we restart main().
+except NameError:
+    A = main.init()
+
+d = main.main(*A)