Add favicon

Change-Id: I26a6a3fdc06a6c620dc9a5950a69519bc12a6d12
diff --git a/inst/rmarkdown/templates/revealjs_presentation/resources/default.html b/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
index 29ee580..85f300d 100644
--- a/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
+++ b/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
@@ -72,7 +72,9 @@
 $if(plugin-customcontrols)$
   <link rel="stylesheet" href="$revealjs-url$/plugin/customcontrols/style.css">
 $endif$
-
+$if(theme-ids)$
+  <link href="https://corpora.ids-mannheim.de/slides/reveal.js.ids/images/favicon2.ico" rel="shortcut icon" type="image/x-icon">
+$endif$
   <style type="text/css">
   /* some tweaks to reveal css */
 $if(theme-dark)$