Rationalized header files:
- mwerks_nonshared_config.h for standalone pythons
- mwerks_shared_config.h for shared pythons (PythonCore, app and
  applet)
- mwerks_plugin_config.h for plugins
Only the _tkinter plugin uses a customized header.

Old config files have gone to the "old" directory, for the time being.
diff --git a/Mac/mwerks/mwerks_plugin_config.h b/Mac/mwerks/mwerks_plugin_config.h
index 519b08b..18d5e67 100644
--- a/Mac/mwerks/mwerks_plugin_config.h
+++ b/Mac/mwerks/mwerks_plugin_config.h
@@ -1 +1,5 @@
-#define HAVE_CONFIG_H
+/*
+** Config file for dynamically-loaded ppc/cfm68k plugin modules.
+*/
+
+#define USE_GUSI		/* Stdio implemented with GUSI */