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/plugin/math/math.esm.js b/inst/reveal.js-4.1.2/plugin/math/math.esm.js
new file mode 100644
index 0000000..716c114
--- /dev/null
+++ b/inst/reveal.js-4.1.2/plugin/math/math.esm.js
@@ -0,0 +1 @@
+function e(e,t){var n=Object.keys(e);if(Object.getOwnPropertySymbols){var r=Object.getOwnPropertySymbols(e);t&&(r=r.filter((function(t){return Object.getOwnPropertyDescriptor(e,t).enumerable}))),n.push.apply(n,r)}return n}function t(t){for(var r=1;r<arguments.length;r++){var a=null!=arguments[r]?arguments[r]:{};r%2?e(Object(a),!0).forEach((function(e){n(t,e,a[e])})):Object.getOwnPropertyDescriptors?Object.defineProperties(t,Object.getOwnPropertyDescriptors(a)):e(Object(a)).forEach((function(e){Object.defineProperty(t,e,Object.getOwnPropertyDescriptor(a,e))}))}return t}function n(e,t,n){return t in e?Object.defineProperty(e,t,{value:n,enumerable:!0,configurable:!0,writable:!0}):e[t]=n,e}export default function(){var e,n={messageStyle:"none",tex2jax:{inlineMath:[["$","$"],["\\(","\\)"]],skipTags:["script","noscript","style","textarea","pre"]},skipStartupTypeset:!0};return{id:"math",init:function(r){var a=(e=r).getConfig().math||{},o=t(t({},n),a),c=(o.mathjax||"https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js")+"?config="+(o.config||"TeX-AMS_HTML-full");o.tex2jax=t(t({},n.tex2jax),a.tex2jax),o.mathjax=o.config=null,function(e,t){var n=this,r=document.querySelector("head"),a=document.createElement("script");a.type="text/javascript",a.src=e;var o=function(){"function"==typeof t&&(t.call(),t=null)};a.onload=o,a.onreadystatechange=function(){"loaded"===n.readyState&&o()},r.appendChild(a)}(c,(function(){MathJax.Hub.Config(o),MathJax.Hub.Queue(["Typeset",MathJax.Hub,e.getRevealElement()]),MathJax.Hub.Queue(e.layout),e.on("slidechanged",(function(e){MathJax.Hub.Queue(["Typeset",MathJax.Hub,e.currentSlide])}))}))}}}
diff --git a/inst/reveal.js-4.1.2/plugin/math/math.js b/inst/reveal.js-4.1.2/plugin/math/math.js
new file mode 100644
index 0000000..6c52bc5
--- /dev/null
+++ b/inst/reveal.js-4.1.2/plugin/math/math.js
@@ -0,0 +1 @@
+!function(e,t){"object"==typeof exports&&"undefined"!=typeof module?module.exports=t():"function"==typeof define&&define.amd?define(t):(e="undefined"!=typeof globalThis?globalThis:e||self).RevealMath=t()}(this,(function(){"use strict";function e(e,t){var n=Object.keys(e);if(Object.getOwnPropertySymbols){var r=Object.getOwnPropertySymbols(e);t&&(r=r.filter((function(t){return Object.getOwnPropertyDescriptor(e,t).enumerable}))),n.push.apply(n,r)}return n}function t(t){for(var r=1;r<arguments.length;r++){var a=null!=arguments[r]?arguments[r]:{};r%2?e(Object(a),!0).forEach((function(e){n(t,e,a[e])})):Object.getOwnPropertyDescriptors?Object.defineProperties(t,Object.getOwnPropertyDescriptors(a)):e(Object(a)).forEach((function(e){Object.defineProperty(t,e,Object.getOwnPropertyDescriptor(a,e))}))}return t}function n(e,t,n){return t in e?Object.defineProperty(e,t,{value:n,enumerable:!0,configurable:!0,writable:!0}):e[t]=n,e}return function(){var e,n={messageStyle:"none",tex2jax:{inlineMath:[["$","$"],["\\(","\\)"]],skipTags:["script","noscript","style","textarea","pre"]},skipStartupTypeset:!0};return{id:"math",init:function(r){var a=(e=r).getConfig().math||{},o=t(t({},n),a),i=(o.mathjax||"https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js")+"?config="+(o.config||"TeX-AMS_HTML-full");o.tex2jax=t(t({},n.tex2jax),a.tex2jax),o.mathjax=o.config=null,function(e,t){var n=this,r=document.querySelector("head"),a=document.createElement("script");a.type="text/javascript",a.src=e;var o=function(){"function"==typeof t&&(t.call(),t=null)};a.onload=o,a.onreadystatechange=function(){"loaded"===n.readyState&&o()},r.appendChild(a)}(i,(function(){MathJax.Hub.Config(o),MathJax.Hub.Queue(["Typeset",MathJax.Hub,e.getRevealElement()]),MathJax.Hub.Queue(e.layout),e.on("slidechanged",(function(e){MathJax.Hub.Queue(["Typeset",MathJax.Hub,e.currentSlide])}))}))}}}}));
diff --git a/inst/reveal.js-4.1.2/plugin/math/plugin.js b/inst/reveal.js-4.1.2/plugin/math/plugin.js
new file mode 100644
index 0000000..eaef379
--- /dev/null
+++ b/inst/reveal.js-4.1.2/plugin/math/plugin.js
@@ -0,0 +1,91 @@
+/**
+ * A plugin which enables rendering of math equations inside
+ * of reveal.js slides. Essentially a thin wrapper for MathJax.
+ *
+ * @author Hakim El Hattab
+ */
+const Plugin = () => {
+
+	// The reveal.js instance this plugin is attached to
+	let deck;
+
+	let defaultOptions = {
+		messageStyle: 'none',
+		tex2jax: {
+			inlineMath: [ [ '$', '$' ], [ '\\(', '\\)' ] ],
+			skipTags: [ 'script', 'noscript', 'style', 'textarea', 'pre' ]
+		},
+		skipStartupTypeset: true
+	};
+
+	function loadScript( url, callback ) {
+
+		let head = document.querySelector( 'head' );
+		let script = document.createElement( 'script' );
+		script.type = 'text/javascript';
+		script.src = url;
+
+		// Wrapper for callback to make sure it only fires once
+		let finish = () => {
+			if( typeof callback === 'function' ) {
+				callback.call();
+				callback = null;
+			}
+		}
+
+		script.onload = finish;
+
+		// IE
+		script.onreadystatechange = () => {
+			if ( this.readyState === 'loaded' ) {
+				finish();
+			}
+		}
+
+		// Normal browsers
+		head.appendChild( script );
+
+	}
+
+	return {
+		id: 'math',
+
+		init: function( reveal ) {
+
+			deck = reveal;
+
+			let revealOptions = deck.getConfig().math || {};
+
+			let options = { ...defaultOptions, ...revealOptions };
+			let mathjax = options.mathjax || 'https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js';
+			let config = options.config || 'TeX-AMS_HTML-full';
+			let url = mathjax + '?config=' + config;
+
+			options.tex2jax = { ...defaultOptions.tex2jax, ...revealOptions.tex2jax };
+
+			options.mathjax = options.config = null;
+
+			loadScript( url, function() {
+
+				MathJax.Hub.Config( options );
+
+				// Typeset followed by an immediate reveal.js layout since
+				// the typesetting process could affect slide height
+				MathJax.Hub.Queue( [ 'Typeset', MathJax.Hub, deck.getRevealElement() ] );
+				MathJax.Hub.Queue( deck.layout );
+
+				// Reprocess equations in slides when they turn visible
+				deck.on( 'slidechanged', function( event ) {
+
+					MathJax.Hub.Queue( [ 'Typeset', MathJax.Hub, event.currentSlide ] );
+
+				} );
+
+			} );
+
+		}
+	}
+
+};
+
+export default Plugin;