Implement virtual destructors in some C++ classes

project/include/graphics/Renderer.h

@@ -16,6 +16,8 @@ namespace lime {
 		
 		public:
 			
+			virtual ~Renderer() {};
+			
 			virtual void Flip () = 0;
 			virtual void* GetContext () = 0;
 			virtual double GetScale () = 0;

project/include/ui/Window.h

@@ -19,6 +19,8 @@ namespace lime {
 		
 		public:
 			
+			virtual ~Window() {};
+			
 			virtual void Alert (const char* message, const char* title) = 0;
 			virtual void Close () = 0;
 			virtual void Focus () = 0;