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/.Rbuildignore b/.Rbuildignore
index 21b0514..d702cba 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -3,7 +3,6 @@
 README.*
 examples/
 
-
 ^codecov\.yml$
 ^\.github$
 ^_pkgdown\.yml$
@@ -11,3 +10,18 @@
 ^pkgdown$
 vignettes/
 ^tests/manual$
+^tools$
+
+inst/reveal.js-[^/]+/.github
+inst/reveal.js-[^/]+/.gitignore
+inst/reveal.js-[^/]+/.npmignore
+inst/reveal.js-[^/]+/CONTRIBUTING.md
+inst/reveal.js-[^/]+/css
+inst/reveal.js-[^/]+/demo.html
+inst/reveal.js-[^/]+/examples
+inst/reveal.js-[^/]+/gulpfile.js
+inst/reveal.js-[^/]+/index.html
+inst/reveal.js-[^/]+/js
+inst/reveal.js-[^/]+/package-lock.json
+inst/reveal.js-[^/]+/package.json
+inst/reveal.js-[^/]+/test