Provide virtual destructors as gcc-4 barks heavily otherwise

eo/src/eoPopulator.h

@@ -46,6 +46,9 @@ public :
     current = dest.end();
   }
 
+    /** @brief Virtual Constructor */
+    virtual ~eoPopulator() {};
+
   struct OutOfIndividuals {};
 
   /** a populator behaves like an iterator. Hence the operator*

eo/src/utils/eoUpdatable.h

@@ -36,9 +36,15 @@
 class eoUpdatable
 {
 public:
+
+    /** @brief Virtual destructor */
+    virtual ~eoUpdatable() {};
+
     virtual void update() = 0;
 };
 
+
+
 /**
    A base class to actually update an eoUpdatable object
 */