Add header and notice

lib/README.txt

@@ -1,3 +1,11 @@
+                           __     _   __            __
+                          [  |   (_) [  |          / /
+                           | |   __   | |.--.     / /
+                           | |  [  |  | '/'`\ \  / /
+                           | |   | |  |  \__/ | / /
+                           [___][___][__;.__.' /_/
+
+
 This folder contains Python 2 modules that are present in normal Python
 distribution but are (for some reason) absent from Ren'Py distribution of
 Python 2. This README.txt file is not included in submod package and only
@@ -7,4 +15,9 @@ repository.
 Discord Presence Submod authors, maintainers and contributors do not claim any
 ownership over any files in this folder (except for this README.txt file) unless
 explicitly stated otherwise. All rights to this source code belong to their
-respective owners.
+respective owners.
+
+Please, do not modify files in this folder and propose changes via pull
+requests. If you believe it is really necessary and there isn't any other way
+around, open an issue instead and describe your problem with these modules
+there. Thank you for your contribution.