Support for subtitles

Added etoolbox possibly can be removed

ruthesis.sty

@@ -127,10 +127,11 @@
     \rulogo{}
     \par\end{center}\vspace{0.7cm}
 }
+\RequirePackage{etoolbox}
 %% TODO: investigate why bold isn't working on the title
 %\droptitle{}% length moves the title position up and down
 \pretitle{\begin{center}\bfseries\Huge}
-\posttitle{\par\end{center}\vspace{1.55cm}}
+\posttitle{\ifstrempty{\thesubtitle}{}{\\\normalfont{\LARGE \thesubtitle}}\par\end{center}\vspace{1.55cm}}
 \preauthor{\begin{center}\Large}
 \postauthor{\par\end{center}\vfill}
 \renewcommand{\maketitlehookc}{\begin{center}\textbf{\Large \theDegreeAbbrv{} \theDocumentType{} in \theProgram}\par\end{center}\vspace{1cm}}