Add copyright note to all files

calibre-plugin/getEncryptionKeyLinux.py

@@ -1,6 +1,15 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
+'''
+Copyright (c) 2021-2023 Leseratte10
+This file is part of the ACSM Input Plugin by Leseratte10
+ACSM Input Plugin for Calibre / acsm-calibre-plugin
+
+For more information, see: 
+https://github.com/Leseratte10/acsm-calibre-plugin
+'''
+
 #@@CALIBRE_COMPAT_CODE@@
 
 import sys, binascii, traceback