delete mediaindex folder on close

Since we're storing media frames too with no disk space management
at the moment, we'll remove the mediaindex folder too on close
just for this testing period

app/window/mainwindow/mainwindow.cpp

@@ -152,6 +152,7 @@ void olive::MainWindow::closeEvent(QCloseEvent *e)
   // FIXME: Test code - We have no cache management and the cache is very much testing only, so we delete it on close
   //                    as to not clog up HDD space
   QDir(GetMediaCacheLocation()).removeRecursively();
+  QDir(GetMediaIndexLocation()).removeRecursively();
   // End test code
 
   QMainWindow::closeEvent(e);