made disrtuctor in DOFVectorInterface virtual

src/amdis/linear_algebra/DOFVectorInterface.hpp

@@ -6,7 +6,7 @@ namespace AMDiS
   {
   public:
     /// Virtual destructor
-    ~DOFVectorInterface() = default;
+    virtual ~DOFVectorInterface() = default;
 
     /// Change dimension of DOFVector to dimension of basis
     virtual void compress() = 0;