Split Normals I (5/5): Add support of split normals to Cycles.

Idea and code by Brecht, many thanks!

Reviewers: brecht

Reviewed By: brecht

CC: campbellbarton, dingto

Differential Revision: https://developer.blender.org/D369

intern/cycles/render/attribute.h

@@ -82,6 +82,7 @@ public:
 	void add(const float3& f);
 	void add(const Transform& f);
 	void add(const VoxelAttribute& f);
+	void add(const char *data);
 
 	static bool same_storage(TypeDesc a, TypeDesc b);
 	static const char *standard_name(AttributeStandard std);