Move to more memory safe implementation of widget holding

Widgets/WidgetText.cpp

@@ -262,7 +262,7 @@ void WidgetText::draw()
 	SDL_FreeSurface(txt_surface);
 }
 
-Widget* WidgetText::builder(const nlohmann::json& j)
+std::unique_ptr<Widget> WidgetText::builder(const nlohmann::json& j)
 {
 	int x = 0;
 	int y = 0;
@@ -299,7 +299,7 @@ Widget* WidgetText::builder(const nlohmann::json& j)
 		return nullptr;
 	}
 
-	return new WidgetText(x, y, width, height,
+	return std::make_unique<WidgetText>(x, y, width, height,
 		text, fit, should_wrap,
 		halign, valign,
 		halign_via_visible, valign_via_visible,