modify source/(black/white.scss) and template/theme.scss
diff --git a/inst/reveal.js-3.3.0/css/theme/source/black.scss b/inst/reveal.js-3.3.0/css/theme/source/black.scss
index 73dfecb..5f7f601 100644
--- a/inst/reveal.js-3.3.0/css/theme/source/black.scss
+++ b/inst/reveal.js-3.3.0/css/theme/source/black.scss
@@ -1,7 +1,7 @@
 /**
  * Black theme for reveal.js. This is the opposite of the 'white' theme.
  *
- * Copyright (C) 2015 Hakim El Hattab, http://hakim.se
+ * By Hakim El Hattab, http://hakim.se
  */
 
 
diff --git a/inst/reveal.js-3.3.0/css/theme/source/white.scss b/inst/reveal.js-3.3.0/css/theme/source/white.scss
index 4c5b647..6758ce0 100644
--- a/inst/reveal.js-3.3.0/css/theme/source/white.scss
+++ b/inst/reveal.js-3.3.0/css/theme/source/white.scss
@@ -1,7 +1,7 @@
 /**
  * White theme for reveal.js. This is the opposite of the 'black' theme.
  *
- * Copyright (C) 2015 Hakim El Hattab, http://hakim.se
+ * By Hakim El Hattab, http://hakim.se
  */