Fix typo in demo document (#63)

Insitute name --> Institute name

beamertheme-pure-minimalistic-demo.tex

@@ -40,7 +40,7 @@
 \title[short title]{This is the normal length of a research paper:
 always longer than you would expect}
 \author{Kai Norman Clasen}
-\institute{Insitute name} 
+\institute{Institute name} 
 \date{\today}
 
 \begin{document}