Added a banner to the shell startup message discussing possible
warnings from personal firewall software.  Added the same text
to README.txt, updated NEWS.txt for release.

M NEWS.txt
M PyShell.py
M README.txt
diff --git a/Lib/idlelib/README.txt b/Lib/idlelib/README.txt
index df0b7b8..101f7eb 100644
--- a/Lib/idlelib/README.txt
+++ b/Lib/idlelib/README.txt
@@ -21,6 +21,11 @@
 magic "reload/import *" incantations are no longer required when editing and
 testing a module two or three steps down the import chain.
 
+(Personal firewall software may warn about the connection IDLE makes to its
+subprocess using this computer's internal loopback interface.  This connection
+is not visible on any external interface and no data is sent to or received
+from the Internet.)
+
 It is possible to interrupt tightly looping user code, even on Windows.
 
 Applications which cannot support subprocesses and/or sockets can still run