Update invaders sample decorator to new handles.

Samples/invaders/src/DecoratorStarfield.cpp

@@ -85,19 +85,19 @@ Rocket::Core::DecoratorDataHandle DecoratorStarfield::GenerateElementData(Rocket
 		star_field->last_update = Shell::GetElapsedTime();
 	}
 
-	return star_field;
+	return reinterpret_cast<Rocket::Core::DecoratorDataHandle>(star_field);
 }
 
 // Called to release element data generated by this decorator.
 void DecoratorStarfield::ReleaseElementData(Rocket::Core::DecoratorDataHandle element_data)
 {
-	delete (StarField*)element_data;
+	delete reinterpret_cast<StarField*>(element_data);
 }
 
 // Called to render the decorator on an element.
 void DecoratorStarfield::RenderElement(Rocket::Core::Element* ROCKET_UNUSED(element), Rocket::Core::DecoratorDataHandle element_data)
 {
-	StarField* star_field = (StarField*)element_data;
+	StarField* star_field = reinterpret_cast<StarField*>(element_data);
 	star_field->Update();
 
 	glDisable(GL_TEXTURE_2D);