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/reveal.js-4.1.2/examples/assets/beeping.txt b/inst/reveal.js-4.1.2/examples/assets/beeping.txt
new file mode 100644
index 0000000..bf41997
--- /dev/null
+++ b/inst/reveal.js-4.1.2/examples/assets/beeping.txt
@@ -0,0 +1,2 @@
+Source: https://freesound.org/people/fennelliott/sounds/379419/
+License: CC0 (public domain)
\ No newline at end of file
diff --git a/inst/reveal.js-4.1.2/examples/assets/beeping.wav b/inst/reveal.js-4.1.2/examples/assets/beeping.wav
new file mode 100644
index 0000000..38747a5
--- /dev/null
+++ b/inst/reveal.js-4.1.2/examples/assets/beeping.wav
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diff --git a/inst/reveal.js-4.1.2/examples/assets/image1.png b/inst/reveal.js-4.1.2/examples/assets/image1.png
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index 0000000..8747594
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+++ b/inst/reveal.js-4.1.2/examples/assets/image1.png
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diff --git a/inst/reveal.js-4.1.2/examples/assets/image2.png b/inst/reveal.js-4.1.2/examples/assets/image2.png
new file mode 100644
index 0000000..6c403a0
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+++ b/inst/reveal.js-4.1.2/examples/assets/image2.png
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