Prevent going out of bound in the master presentation

Signed-off-by: Paul-Elliot <[email protected]>

example/slipIntroduction.html

@@ -35,7 +35,7 @@
 		<slip-title>Slip.js</slip-title>       <!-- Beamer style title   -->
 		<slip-body>     <!-- Beamer style margin  -->
 		    <ul>
-			<li><span emphasize-at="0">Slip.js</span> is a "slide" engine written in javascript.</li>
+			<li><span emphasize-at="0">Slipshow</span> is a "slide" engine written in javascript.</li>
 			<li pause>Its goal is to keep the best from both worlds of:
 			    <ul>
 				<li><span emphasize-at="1">Beamer</span>, its simplicity to create slides without worrying too much on presentation.</li>

src/modules/engine.mjs

@@ -275,6 +275,10 @@ export default function (root) {
 		this.gotoSlip(newCurrentSlip);
 	    return true;
 	}
+        if (currentSlip.element.tagName == "SLIP-SLIPSHOW" && currentSlip.getActionIndex() >= currentSlip.getMaxNext()) {
+            this.previous();
+            return false
+        }
 	return false;
     };
     this.nextSlip = function () {
@@ -315,6 +319,10 @@ export default function (root) {
 		// this.gotoSlip(newCurrentSlip, {delay: currentSlip.delay});
 	    // this.showToC();
 	    this.updateCounter();
+            if (currentSlip.element.tagName == "SLIP-SLIPSHOW" && currentSlip.getActionIndex() <= 0) {
+                this.next();
+                return true
+            }
 	    return true;
 	} else if(options){
 	    setTimeout(() => {