Use package option to \protect frame titles

Using \protect disables the MakeLowercase command which looks weird with titles
set in small caps. For all those who want to use \cite, \ref and co. can now use
the `protectframetitles` package option.

README.md

@@ -43,6 +43,10 @@ progress bar underneath *each* frame title
 
   ![Progressbar](http://i.imgur.com/4BXHU4K.png)
 
+In order to use `\cite`, `\ref` and similar commands in a frame title you have
+to protect the title. This can be done automatically with the
+`protectframetitle` option.
+
 
 #### Commands
 

beamerthemem.sty

@@ -29,6 +29,10 @@
 \@useTitleProgressBarfalse
 \DeclareOption{titleprogressbar}{\@useTitleProgressBartrue}
 
+\newif\if@protectFrameTitle
+\@protectFrameTitlefalse
+\DeclareOption{protectframetitle}{\@protectFrameTitletrue}
+
 \ProcessOptions\relax
 
 %}}}
@@ -206,7 +210,11 @@
 \setbeamertemplate{frametitle}{%
 \nointerlineskip
 \begin{beamercolorbox}[wd=\paperwidth,leftskip=0.3cm,rightskip=0.3cm,ht=2.5ex,dp=1.5ex]{frametitle}
+\if@protectFrameTitle
   \usebeamerfont{frametitle}\MakeLowercase{\protect\insertframetitle}%
+\else
+  \usebeamerfont{frametitle}\MakeLowercase{\insertframetitle}%
+\fi
 \end{beamercolorbox}%
 \if@useTitleProgressBar
   \vspace{-.6em}