Add options for title graphic and logo

Allow specification of a title graphic and/or logo for Beamer.

default.beamer

@@ -227,6 +227,12 @@ $if(institute)$
 \institute{$for(institute)$$institute$$sep$ \and $endfor$}
 $endif$
 \date{$date$}
+$if(titlegraphic)$
+\titlegraphic{\includegraphics{$titlegraphic$}}
+$endif$
+$if(logo)$
+\logo{\includegraphics{$logo$}}
+$endif$
 
 \begin{document}
 $if(title)$