Rename uiveonim_nyancat.png -> uivonim_nyancat.png

Author: smolck

images/showcase/uiveonim_nyancat.png renamed to images/showcase/uivonim_nyancat.png

@@ -36,7 +36,7 @@ <h5>Treeview and an externalized popup menu in <a href="https://github.com/equal
 
       <li>
         <h5>Nyancat in <a href="https://github.com/smolck/uivonim">Uivonim</a></h5>
-        <img src="/images/showcase/uiveonim_nyancat.png" alt="uivonim (courtesy of @smolck)" width="80%"/>
+        <img src="/images/showcase/uivonim_nyancat.png" alt="uivonim (courtesy of @smolck)" width="80%"/>
       </li>
 
       <li>