Renderer/Renderer: Replace listeners by signals

Former-commit-id: c1293f7f7cc31c4122ba866fc44d93188917ad93

include/Nazara/Utility/VertexBuffer.hpp

@@ -11,6 +11,7 @@
 #include <Nazara/Core/ObjectListenerWrapper.hpp>
 #include <Nazara/Core/ObjectRef.hpp>
 #include <Nazara/Core/RefCounted.hpp>
+#include <Nazara/Core/Signal.hpp>
 #include <Nazara/Utility/Buffer.hpp>
 #include <Nazara/Utility/VertexDeclaration.hpp>
 
@@ -64,6 +65,8 @@ class NAZARA_API NzVertexBuffer : public NzRefCounted
 
 		template<typename... Args> static NzVertexBufferRef New(Args&&... args);
 
+		NazaraSignal(OnVertexBufferRelease, const NzVertexBuffer*); //< me
+
 	private:
 		NzBufferRef m_buffer;
 		NzVertexDeclarationConstRef m_vertexDeclaration;