Update to reveal.js 4.1.2 (#136)

- New tools/ script to manually keep step for updates
- Plugins are all updated
- Template update following latest Pandoc version
- updated README for documentation
- Help page updated 
- See other change in NEWS file
diff --git a/inst/NOTICE b/inst/NOTICE
index bfe3f00..cdaef8c 100644
--- a/inst/NOTICE
+++ b/inst/NOTICE
@@ -8,7 +8,7 @@
 reveal.js
 -----------------------------------------------------------------------
 
-Copyright (C) 2013 Hakim El Hattab, http://hakim.se
+Copyright (C) 2020 Hakim El Hattab, http://hakim.se, and reveal.js contributors
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal