Revert "deleted getlayers function"

This reverts commit 0dbb8bc642.

SakuraCore/src/LayerStack.h

@@ -37,6 +37,10 @@ public:
     void SubmitCommand(LayerCommand command);
     void ProcessCommands();
 
+#ifdef DEBUG
+    // this is only used for the tests for now, so it will be taken out of the release build
+    inline const std::vector<std::unique_ptr<Layer>> &GetLayers() const { return m_LayerStack; }
+#endif
 private:
     std::vector<LayerCommand> m_CommandQueue;
     std::vector<std::unique_ptr<Layer>> m_LayerStack;