v0.2.55..v0.2.56 changeset DataFrame.h

diff --git a/tgs/src/main/cpp/tgs/RandomForest/DataFrame.h b/tgs/src/main/cpp/tgs/RandomForest/DataFrame.h
index 83d3329..45b0e1e 100644
--- a/tgs/src/main/cpp/tgs/RandomForest/DataFrame.h
+++ b/tgs/src/main/cpp/tgs/RandomForest/DataFrame.h
@@ -22,7 +22,7 @@
  * This will properly maintain the copyright information. DigitalGlobe
  * copyrights will be updated automatically.
  *
- * @copyright Copyright (C) 2015, 2016, 2017, 2018, 2019 DigitalGlobe (http://www.digitalglobe.com/)
+ * @copyright Copyright (C) 2015, 2016, 2017, 2018, 2019, 2020 DigitalGlobe (http://www.digitalglobe.com/)
  */
 
 #ifndef __DATA_FRAME_H__
@@ -79,7 +79,7 @@ namespace Tgs
     /**
     * Destructor
     */
-    ~DataFrame();
+    virtual ~DataFrame();
 
     /**
     * Appends a data vector to the end of the dataframe