Moved Model::EnableDraw to SceneNode::EnableDrawing

Same goes for Model::IsDrawEnabled() => SceneNode::IsDrawingEnabled()
Is Drawable is now a pure virtual method from SceneNode


Former-commit-id: 217c6a21a98206ee0b283aaa216d419696a70faf

include/Nazara/Graphics/Sprite.hpp

@@ -27,6 +27,8 @@ class NAZARA_API NzSprite : public NzSceneNode
 		const NzVector2f& GetSize() const;
 		const NzRectf& GetTextureCoords() const;
 
+		bool IsDrawable() const;
+
 		void SetMaterial(NzMaterial* material);
 		void SetSize(const NzVector2f& size);
 		void SetTextureCoords(const NzRectf& coords);