Add virtual destructor for Sound

Author: frabert

src/audio/AudioEngine.h

@@ -30,6 +30,8 @@ namespace Audio
      */
     class Sound {
     public:
+        virtual ~Sound() = default;
+
         /**
          * @brief Set sound pitch, must be positive
          * 

src/audio/OpenALAudioEngine.cpp

@@ -169,7 +169,7 @@ namespace Audio
             }
         }
 
-        virtual ~OpenALSound()
+        ~OpenALSound() override
         {
             if (m_hasSource)
             {