Revert "Graphics/RenderTechnique: Remove Clear method"

This reverts commit 8aa3764660d5c98995135f736ecd710677fa240c [formerly 9b4ec3ae32492e383c19a06bd1c3e461b3fcf46d].

It seems I was wrong about the Clear method, my revert broke the Deferred Rendering


Former-commit-id: b8d2db34ffd9d24798670f19aba0de88f5b77a1c

SDK/src/NDK/Systems/RenderSystem.cpp

@@ -99,6 +99,7 @@ namespace Ndk
 			sceneData.background = m_background;
 			sceneData.viewer = &camComponent;
 
+			m_renderTechnique.Clear(sceneData);
 			m_renderTechnique.Draw(sceneData);
 		}
 	}