add section headers

doc/slides/slides.tex

@@ -10,6 +10,17 @@
     Page~\insertframenumber{}
 }
 
+\AtBeginSection[]{
+  \begin{frame}
+  \vfill
+  \centering
+  \begin{beamercolorbox}[sep=8pt,center,shadow=true,rounded=true]{title}
+    \usebeamerfont{title}\insertsectionhead\par%
+  \end{beamercolorbox}
+  \vfill
+  \end{frame}
+}
+
 % set up citations
 
 \usepackage[